fix(scene): resume chunk downloads after proxy interruptions

Whole-file loading still failed after adding caching because the public proxy interrupted large GLB response bodies. Download validated 1 MiB ranges, retry transient failures up to three attempts, and persist completed chunks so reloads resume from their last boundary.

Add regression cases observed failing before the change for interrupted downloads, cross-reload resume, and temporary HTTP failures. Verify range integrity, full-cache reuse, permanent errors, and storage fallback.

docs/scene-resource-cache.md

@@ -0,0 +1,19 @@
+# 三维场景静态资源下载与缓存
+
+`public/three-dimensional/zjb/v29/resourceCache.mjs` 统一加载模型和管网静态元数据，不缓存实时仿真或 SCADA 数据。
+
+- 每次请求最多下载 1 MiB，通过单区间 `Range` 请求获取资源。服务器返回 `206` 时，校验 `Content-Range` 的起止位置、总长度以及实际收到的字节数；不支持 Range 的服务器可在首次请求返回完整的 `200` 响应。
+- 网络中断、连续 30 秒无数据以及临时 HTTP 错误可重试，每个分段最多尝试 3 次，等待间隔为 300、600 毫秒。永久 HTTP 错误和不合法的分段响应直接显示失败提示。
+- 每个完整分段保存至 IndexedDB。刷新页面或重新载入后，从已保存的分段末尾继续；未完成的当前分段会重新下载。浏览器禁止存储或配额不足时，仍能在本次加载中下载和重试，但无法保证刷新后保留断点。
+- 完整资源和部分下载均按 URL、manifest revision 匹配，版本改变后重新下载。完整资源经过解析验证后才进入正式缓存，后续打开场景直接复用。
+- 进度界面显示下载、解析和断点重试状态。加载模块版本参数需要与 `preview.html`、`preview.mjs` 和 `ThreeDimensionalScene.tsx` 同步，防止浏览器沿用旧加载器。
+
+反向代理应透传 `Range` 请求及 `206`、`Content-Range` 响应。若内网完整下载正常，而公网完整下载中断，应同时排查代理的大文件传输；客户端分段恢复不代表代理链路问题已修复。
+
+聚焦回归：
+
+```bash
+E2E_BASE_URL=http://127.0.0.1:3000 npx playwright test e2e/three-dimensional-loading.spec.ts --workers=1
+```
+
+该命令需要已运行的前端。测试覆盖完整缓存复用、分段重试、跨刷新续传、错误分段拒绝及浏览器存储不可用的降级行为。

e2e/three-dimensional-loading.spec.ts

@@ -1,7 +1,7 @@
 import { expect, test } from "@playwright/test";
 
 const root = "/three-dimensional/zjb/v29/";
-const preview = root + "preview.html?host=platform2&v=35-resource-cache";
+const preview = root + "preview.html?host=platform2&v=36-resumable-cache";
 const isAsset = (url: string) => /\.glb(?:\?|$)|water-network-v28\.json/.test(url);
 
 test.setTimeout(120_000);
@@ -28,7 +28,7 @@ test("HTTP 200 的错误元数据不会进入缓存，服务器恢复后重试
   expect(cached).toBe(false);
   await page.getByRole("button", { name: "重新载入场景" }).click();
   await expect(page.locator("#boot")).toBeHidden({ timeout: 60_000 });
-  expect(requests).toBe(2);
+  expect(requests).toBe(5);
 });
 
 test("模型和元数据跨页面复用持久缓存，即使服务器资源不可用也能重开场景", async ({ page, context }) => {
@@ -46,7 +46,7 @@ test("模型和元数据跨页面复用持久缓存，即使服务器资源不
   await page.goto(preview);
   await expect(page.locator("#boot")).toBeHidden({ timeout: 60_000 });
   const coldMs = Date.now() - coldStart;
-  expect(requests).toHaveLength(10);
+  expect(new Set(requests).size).toBe(10);
   requests.length = 0;
   block = true;
   await page.close();
@@ -140,7 +140,7 @@ test("HTTP 错误和解析失败不会写入缓存，下一次请求可恢复",
   await page.route("**/cache-probe.json*", (route) => {
     requests++;
     return requests === 1
-      ? route.fulfill({ status: 503, body: "unavailable" })
+      ? route.fulfill({ status: 404, body: "not found" })
       : requests === 2
         ? route.fulfill({ body: "invalid json" })
         : route.fulfill({ json: { ok: true } });
@@ -160,6 +160,145 @@ test("HTTP 错误和解析失败不会写入缓存，下一次请求可恢复",
   }, root);
   expect(requests).toBe(3);
   expect(result.errors).toHaveLength(2);
-  expect(result.errors[0]).toContain("HTTP 503");
+  expect(result.errors[0]).toContain("HTTP 404");
   expect(result.recovered).toEqual({ ok: true });
 });
+
+test("公网整文件中断时分段下载，重试失败分段并缓存完整模型", async ({ page }) => {
+  const { readFile } = await import("node:fs/promises");
+  const { createHash } = await import("node:crypto");
+  const bytes = await readFile("public/three-dimensional/zjb/v29/models/detail_interior.glb");
+  const ranges: string[] = [];
+  let interrupted = false;
+  await page.route("**/models/detail_interior.glb*", async (route) => {
+    const range = route.request().headers().range;
+    ranges.push(range ?? "whole-file");
+    // The public proxy drops whole-file responses, and one partial request drops too.
+    if (!range) return route.abort("failed");
+    if (range.startsWith("bytes=1048576-") && !interrupted) {
+      interrupted = true;
+      return route.abort("failed");
+    }
+    const match = /^bytes=(\d+)-(\d+)$/.exec(range)!;
+    const start = Number(match[1]);
+    const end = Math.min(Number(match[2]), bytes.length - 1);
+    return route.fulfill({ status: 206, headers: {
+      "content-type": "model/gltf-binary",
+      "content-range": `bytes ${start}-${end}/${bytes.length}`,
+    }, body: bytes.subarray(start, end + 1) });
+  });
+  await page.goto(root + "manifest.json");
+  const result = await page.evaluate(async (base) => {
+    const { createSceneResourceCache } = await import(base + "resourceCache.mjs");
+    const load = () => createSceneResourceCache(location.origin + base).load("models/detail_interior.glb", "range-recovery");
+    const data = await load();
+    const cached = await load();
+    return { length: data.byteLength, cachedLength: cached.byteLength,
+      sha256: Array.from(new Uint8Array(await crypto.subtle.digest("SHA-256", data)), n => n.toString(16).padStart(2, "0")).join("") };
+  }, root);
+  expect(result).toEqual({ length: bytes.length, cachedLength: bytes.length, sha256: createHash("sha256").update(bytes).digest("hex") });
+  expect(ranges).toHaveLength(7);
+  expect(ranges[0]).toBe("bytes=0-1048575");
+  expect(ranges[1]).toBe(ranges[2]);
+  expect(interrupted).toBe(true);
+});
+
+for (const fault of ["offset", "total", "truncated", "whole-response"] as const) {
+  test(`无效分段响应 ${fault} 不会进入缓存，恢复后可重新下载`, async ({ page }) => {
+    const bytes = Buffer.alloc(1048576 + 16, 7);
+    let broken = true;
+    let requests = 0;
+    await page.route("**/range-probe.bin*", (route) => {
+      requests++;
+      const range = route.request().headers().range;
+      if (!range) return route.abort("failed");
+      const match = /^bytes=(\d+)-(\d+)$/.exec(range)!;
+      const start = Number(match[1]);
+      const end = Math.min(Number(match[2]), bytes.length - 1);
+      if (broken && start > 0 && fault === "whole-response") return route.fulfill({ body: bytes });
+      return route.fulfill({ status: 206, headers: {
+        "content-range": `bytes ${broken && start > 0 && fault === "offset" ? 0 : start}-${end}/${bytes.length + (broken && start > 0 && fault === "total" ? 1 : 0)}`,
+      }, body: bytes.subarray(start, end + (broken && start > 0 && fault === "truncated" ? 0 : 1)) });
+    });
+    await page.goto(root + "manifest.json");
+    const failed = await page.evaluate(async (base) => {
+      const { createSceneResourceCache } = await import(base + "resourceCache.mjs");
+      try { await createSceneResourceCache(location.origin + base).load("range-probe.bin", "first"); return false; }
+      catch { return true; }
+    }, root);
+    expect(failed).toBe(true);
+    const before = requests;
+    broken = false;
+    const length = await page.evaluate(async (base) => {
+      const { createSceneResourceCache } = await import(base + "resourceCache.mjs");
+      return (await createSceneResourceCache(location.origin + base).load("range-probe.bin", "first")).byteLength;
+    }, root);
+    expect(length).toBe(bytes.length);
+    // The valid first segment survives; only the rejected final segment is fetched again.
+    expect(requests - before).toBe(1);
+  });
+}
+
+test("下载中断后刷新页面，从已保存的分段继续下载", async ({ page }) => {
+  const bytes = Buffer.alloc(2 * 1048576 + 16, 9);
+  let disconnected = true;
+  const ranges: string[] = [];
+  await page.route("**/resume-probe.bin*", (route) => {
+    const range = route.request().headers().range;
+    ranges.push(range ?? "whole-file");
+    if (!range) return route.abort("failed");
+    const match = /^bytes=(\d+)-(\d+)$/.exec(range)!;
+    const start = Number(match[1]);
+    const end = Math.min(Number(match[2]), bytes.length - 1);
+    if (disconnected && start > 0) return route.abort("failed");
+    return route.fulfill({ status: 206, headers: { "content-range": `bytes ${start}-${end}/${bytes.length}` }, body: bytes.subarray(start, end + 1) });
+  });
+  await page.goto(root + "manifest.json");
+  const load = (base: string) => page.evaluate(async (base) => {
+    const { createSceneResourceCache } = await import(base + "resourceCache.mjs");
+    try {
+      const data = await createSceneResourceCache(location.origin + base).load("resume-probe.bin", "first");
+      return { length: data.byteLength, failed: false };
+    } catch { return { failed: true }; }
+  }, base);
+  expect(await load(root)).toEqual({ failed: true });
+  expect(ranges.filter(range => range === "bytes=1048576-2097151")).toHaveLength(3);
+  disconnected = false;
+  ranges.length = 0;
+  await page.reload();
+  expect(await load(root)).toEqual({ length: bytes.length, failed: false });
+  expect(ranges).toEqual(["bytes=1048576-2097151", "bytes=2097152-2097167"]);
+});
+
+test("临时 HTTP 503 自动重试，成功后才写入缓存", async ({ page }) => {
+  let requests = 0;
+  await page.route("**/retry-probe.json*", (route) => {
+    requests++;
+    return requests < 3 ? route.fulfill({ status: 503, body: "unavailable" }) : route.fulfill({ json: { ok: true } });
+  });
+  await page.goto(root + "manifest.json");
+  const result = await page.evaluate(async (base) => {
+    const { createSceneResourceCache } = await import(base + "resourceCache.mjs");
+    const stages: string[] = [];
+    const cache = createSceneResourceCache(location.origin + base, ({ stage }: { stage: string }) => stages.push(stage));
+    const data = await cache.load("retry-probe.json", "first", (data: ArrayBuffer) => JSON.parse(new TextDecoder().decode(data)));
+    return { data, retries: stages.filter(stage => stage === "retry").length };
+  }, root);
+  expect(result).toEqual({ data: { ok: true }, retries: 2 });
+  expect(requests).toBe(3);
+});
+
+test("服务器返回空的完整响应时只解析一次，不循环下载", async ({ page }) => {
+  let requests = 0;
+  await page.route("**/empty-probe.json*", (route) => { requests++; return route.fulfill({ body: "" }); });
+  await page.goto(root + "manifest.json");
+  const failed = await page.evaluate(async (base) => {
+    const { createSceneResourceCache } = await import(base + "resourceCache.mjs");
+    try {
+      await createSceneResourceCache(location.origin + base).load("empty-probe.json", "first", (data: ArrayBuffer) => JSON.parse(new TextDecoder().decode(data)));
+      return false;
+    } catch { return true; }
+  }, root);
+  expect(failed).toBe(true);
+  expect(requests).toBe(1);
+});

public/three-dimensional/zjb/v29/loadingProgress.mjs

@@ -32,12 +32,13 @@ export function reportProgress(update) {
  const done = values.filter(item => item.stage === 'ready').length;
  const loaded = values.reduce((sum, item) => sum + item.loaded, 0);
  const cached = values.filter(item => item.stage === 'cache').length;
+ const retrying = values.some(item => item.stage === 'retry');
  const parsing = values.some(item => item.stage === 'parse');
  const downloading = values.some(item => item.stage === 'download');
  progress.max = Math.max(1, values.length);
  progress.value = done;
  title.textContent = `正在载入场景资源 ${done} / ${values.length}`;
- detail.textContent = `${parsing ? '正在解析模型' : downloading ? '正在下载资源' : cached ? '正在读取本地缓存' : '正在准备场景'} · 已读取 ${formatBytes(loaded)}`;
+ detail.textContent = `${retrying ? '连接中断，正在从断点重试' : parsing ? '正在解析模型' : downloading ? '正在下载资源' : cached ? '正在读取本地缓存' : '正在准备场景'} · 已读取 ${formatBytes(loaded)}`;
 }
 
 export function finishLoading() {

public/three-dimensional/zjb/v29/preview.html

@@ -36,8 +36,8 @@
     </div>
     <output id="qa" hidden></output>
     <script type="module">
-      import {failLoading} from './loadingProgress.mjs?v=35-resource-cache';
+      import {failLoading} from './loadingProgress.mjs?v=36-resumable-cache';
-      import('./preview.mjs?v=35-resource-cache').catch(failLoading);
+      import('./preview.mjs?v=36-resumable-cache').catch(failLoading);
     </script>
   </body>
 </html>

public/three-dimensional/zjb/v29/preview.mjs

@@ -1,7 +1,7 @@
 import {createRenderEffects} from './render-effects.mjs';
-import {createCameraNavigation,framePose} from './camera-navigation.mjs?v=35-resource-cache';
+import {createCameraNavigation,framePose} from './camera-navigation.mjs?v=36-resumable-cache';
-import {createSceneResourceCache} from './resourceCache.mjs?v=35-resource-cache';
+import {createSceneResourceCache} from './resourceCache.mjs?v=36-resumable-cache';
-import {beginLoading,reportProgress,finishLoading,failLoading} from './loadingProgress.mjs?v=35-resource-cache';
+import {beginLoading,reportProgress,finishLoading,failLoading} from './loadingProgress.mjs?v=36-resumable-cache';
 import {createAssetInspector} from './asset-inspector.mjs?v=29-platform2';
 import * as THREE from 'three';
 import {GLTFLoader} from 'three/addons/loaders/GLTFLoader.js';

public/three-dimensional/zjb/v29/resourceCache.mjs

@@ -2,6 +2,8 @@
 const DATABASE = 'tjwater-scene-assets-v1';
 const STORE = 'resources';
 const REQUEST_TIMEOUT_MS = 30_000;
+const CHUNK_BYTES = 1024 * 1024;
+const MAX_ATTEMPTS = 3;
 
 function openDatabase() {
  return new Promise(resolve => {
@@ -54,39 +56,111 @@ export function createSceneResourceCache(baseUrl, onProgress = () => {}) {
 
   // Revisioned URLs also keep the browser's HTTP cache in sync with the manifest.
   if (revision) url.searchParams.set('v', revision);
-  const controller = new AbortController();
+  const partialKey = key + '#partial';
-  let timer;
+  let chunks = [], loaded = 0, total = 0;
-  const resetTimeout = () => {
+  if (storage && revision) {
-   clearTimeout(timer);
+   try {
-   timer = setTimeout(() => controller.abort(), REQUEST_TIMEOUT_MS);
+    const partial = await transact(storage, 'readonly', store => store.get(partialKey));
-  };
+    if (partial?.revision === revision && Number.isSafeInteger(partial.total) && partial.total > 0 &&
-  report('download');
+        Array.isArray(partial.chunks) && partial.chunks.length &&
-  resetTimeout();
+        partial.chunks.every(chunk => chunk instanceof ArrayBuffer && chunk.byteLength > 0 && chunk.byteLength <= CHUNK_BYTES)) {
-  let data;
+     const size = partial.chunks.reduce((sum, chunk) => sum + chunk.byteLength, 0);
-  try {
+     if (size <= partial.total) { chunks = partial.chunks; loaded = size; total = partial.total; }
-   const response = await fetch(url, {signal:controller.signal, cache:'no-cache'});
-   if (!response.ok) throw Error('HTTP ' + response.status);
-   const total = Number(response.headers.get('content-length')) || 0;
-   if (response.body) {
-    const reader = response.body.getReader();
-    const chunks = [];
-    let loaded = 0;
-    while (true) {
-     const {done, value} = await reader.read();
-     if (done) break;
-     chunks.push(value); loaded += value.byteLength;
-     report('download', loaded, total); resetTimeout();
     }
-    const bytes = new Uint8Array(loaded);
+   } catch { /* A denied partial cache does not prevent downloading. */ }
+  }
+
+  async function downloadPart() {
+   const controller = new AbortController();
+   let timer;
+   const resetTimeout = () => {
+    clearTimeout(timer);
+    timer = setTimeout(() => controller.abort(), REQUEST_TIMEOUT_MS);
+   };
+   resetTimeout();
+   try {
+    const end = total ? Math.min(loaded + CHUNK_BYTES, total) - 1 : loaded + CHUNK_BYTES - 1;
+    const response = await fetch(url, {signal:controller.signal, cache:'no-cache', headers:{Range:`bytes=${loaded}-${end}`}});
+    if (!response.ok) {
+     const error = Error('HTTP ' + response.status);
+     error.retryable = [408, 429, 500, 502, 503, 504].includes(response.status);
+     throw error;
+    }
+    let partTotal = 0, expected = 0;
+    if (response.status === 206) {
+     const range = /^bytes (\d+)-(\d+)\/(\d+)$/.exec(response.headers.get('content-range') ?? '');
+     const start = Number(range?.[1]), last = Number(range?.[2]);
+     partTotal = Number(range?.[3]);
+     if (!range || start !== loaded || last < start || last > end || last >= partTotal ||
+         !Number.isSafeInteger(partTotal) || (total && total !== partTotal)) {
+      throw Error('资源分段响应无效');
+     }
+     expected = last - start + 1;
+    } else {
+     if (loaded) throw Error('服务器未按断点返回资源');
+     // Servers without Range support can still return an ordinary complete response.
+     partTotal = Number(response.headers.get('content-length')) || 0;
+    }
+    const buffers = [];
+    let size = 0;
+    if (response.body) {
+     const reader = response.body.getReader();
+     try {
+      while (true) {
+       const {done, value} = await reader.read();
+       if (done) break;
+       buffers.push(value); size += value.byteLength;
+       if (expected && size > expected) throw Error('资源分段长度无效');
+       report('download', loaded + size, partTotal); resetTimeout();
+      }
+     } finally { await reader.cancel().catch(() => {}); }
+    } else {
+     const buffer = new Uint8Array(await response.arrayBuffer());
+     buffers.push(buffer); size = buffer.byteLength;
+    }
+    if (expected && size !== expected) throw Error('资源分段不完整');
+    const bytes = new Uint8Array(size);
     let offset = 0;
-    for (const chunk of chunks) { bytes.set(chunk, offset); offset += chunk.byteLength; }
+    for (const buffer of buffers) { bytes.set(buffer, offset); offset += buffer.byteLength; }
-    data = bytes.buffer;
+    return {data:bytes.buffer, total:response.status === 206 ? partTotal : size, ranged:response.status === 206};
-   } else {
+   } catch (error) {
-    data = await response.arrayBuffer();
+    controller.abort();
+    throw error;
+   } finally { clearTimeout(timer); }
+  }
+
+  report('download', loaded, total);
+  try {
+   while (!total || loaded < total) {
+    let part;
+    for (let attempt = 0; attempt < MAX_ATTEMPTS; attempt++) {
+     try { part = await downloadPart(); break; }
+     catch (error) {
+      // Permanent HTTP/contract errors stop; temporary transport/server errors can recover.
+      if (!error.retryable && !(error instanceof TypeError) && error.name !== 'AbortError' && error.message !== '资源分段不完整') throw error;
+      if (attempt + 1 === MAX_ATTEMPTS) throw error;
+      report('retry', loaded, total);
+      await new Promise(resolve => setTimeout(resolve, 300 * (attempt + 1)));
+     }
+    }
+    chunks.push(part.data); loaded += part.data.byteLength; total = part.total;
+    if (storage && revision && part.ranged) {
+     try { await transact(storage, 'readwrite', store => store.put({url:partialKey, revision, total, chunks})); }
+     catch { /* Storage denied/full: retain the in-memory download. */ }
+    }
+    if (!part.ranged) break;
    }
   } catch (error) {
-   throw Error(file + '：' + (controller.signal.aborted ? '下载超时，请重试' : error.message));
+   throw Error(file + '：' + (error.name === 'AbortError' ? '下载超时，请重试' : error.message));
-  } finally { clearTimeout(timer); }
+  }
+  const bytes = new Uint8Array(loaded);
+  let offset = 0;
+  for (const chunk of chunks) { bytes.set(new Uint8Array(chunk), offset); offset += chunk.byteLength; }
+  const data = bytes.buffer;
+  if (storage) {
+   try { await transact(storage, 'readwrite', store => store.delete(partialKey)); }
+   catch { /* Completed bytes can still be parsed when storage is unavailable. */ }
+  }
 
   report('parse', data.byteLength, data.byteLength);
   // Validate/parse before persisting so an HTML error page or bad GLB cannot poison the cache.

src/components/threeDimensional/ThreeDimensionalScene.tsx

@@ -38,7 +38,7 @@ import {
   type SceneRuntimeState,
 } from "./sceneProtocol";
 
-const SCENE_URL = "/three-dimensional/zjb/v29/preview.html?host=platform2&v=35-resource-cache";
+const SCENE_URL = "/three-dimensional/zjb/v29/preview.html?host=platform2&v=36-resumable-cache";
 const SCENE_LOAD_TIMEOUT_MS = 120_000;
 
 const initialRuntimeState: SceneRuntimeState = {