fix(reader): split large txt into chapters (章 as boundaries, 卷 as optgroup labels, pseudo-sections when unmarked) rendered one at a time so the browser stops freezing; decode via strict-UTF-8-then-GB18030 with UTF-16 BOM sniffing to kill mojibake; progress locator {ch,scrollFraction} with old global-fraction fallback

docs/CHANGELOG_web.md

@@ -8,6 +8,13 @@ The format loosely follows Keep a Changelog and can be adapted to the team's hab
 
 ## [Unreleased]
 
+### Fixed / 修复
+
+- .txt/.md files encoded in GBK/GB2312/GB18030 or UTF-16 (typical web-novel exports) no longer render as mojibake: the reader strictly tries UTF-8 first and falls back to GB18030, recognizing UTF-16 by BOM.
+- GBK/GB2312/GB18030 或 UTF-16 编码的 .txt/.md（网文导出常见）不再乱码：阅读器先按 UTF-8 严格解码，失败自动回退 GB18030，UTF-16 靠 BOM 识别。
+- Reading a large .txt no longer freezes the browser: the text is split into chapters (「第X章」/Chapter X/序章… markers, pseudo-sections for unmarked files) and rendered one chapter at a time with a chapter selector and prev/next navigation; 「第X卷/部」 are volume groupings (dropdown optgroups), not chapter breaks, and books with only volumes split by volume; reading progress restores to the saved chapter.
+- 阅读大 txt 不再卡死浏览器：正文按章节切分（识别「第X章」/Chapter X/序章等标题，无标记的按段落切成小节），每次只渲染一章，并提供章节目录选择与上一章/下一章导航；「第X卷/部」按卷分组（下拉框分组标签）而非章节边界，只有卷没有章的书按卷切分；阅读进度会恢复到上次的章节。
+
 ### Changed / 变更
 
 - Creating a library on the admin Libraries page no longer asks for a server-side absolute path; just a name (the directory lands at `BOOKS_DIR/<name>` automatically).

frontend/src/lib/chapters.ts

@@ -0,0 +1,65 @@
+// txt 章节切分:优先识别「第X章」类标题行;「第X卷/部」是层级不是章节边界,
+// 只做分组标签;整本没有章标记时才退而用卷作边界;再没有就按段落边界切
+// 伪章节,保证任何单块都能在浏览器里流畅渲染。纯逻辑,无 DOM,vitest 覆盖。
+export interface TxtChapter {
+  title: string;
+  start: number; // 正文中的起始字符偏移(含标题行本身)
+  vol?: string; // 所属卷标题(仅用于导航分组)
+}
+
+const NUM = "[0-9〇零一二三四五六七八九十百千万两]+";
+const CH_RE = new RegExp(
+  `^[ \\t\\u3000]*(?:第\\s*${NUM}\\s*[章节回篇话]|Chapter\\s+${NUM}|序[章言]|楔子|引子|尾声|终章|后记|番外)[^\\n]{0,60}[ \\t]*$`,
+  "gim",
+);
+const VOL_RE = new RegExp(`^[ \\t\\u3000]*第\\s*${NUM}\\s*[卷部][^\\n]{0,60}[ \\t]*$`, "gm");
+
+const MIN_GAP = 200; // 距上一保留标题不足此数视为目录行/正文提及,丢弃
+const CHUNK = 20_000; // 伪章节目标字数
+
+function markers(text: string, re: RegExp): TxtChapter[] {
+  const out: TxtChapter[] = [];
+  for (const m of text.matchAll(re)) {
+    const i = m.index ?? 0;
+    if (out.length && i - out[out.length - 1].start < MIN_GAP) continue;
+    out.push({ title: m[0].trim().slice(0, 40), start: i });
+  }
+  return out;
+}
+
+export function splitChapters(text: string): TxtChapter[] {
+  const vols = markers(text, VOL_RE);
+  let chs = markers(text, CH_RE);
+  let volMarks = vols;
+  if (chs.length < 2 && vols.length > 1) {
+    chs = vols; // 只有卷的书:卷即章节
+    volMarks = [];
+  }
+  if (chs.length > 1) {
+    if (chs[0].start > MIN_GAP) chs.unshift({ title: "开篇", start: 0 });
+    for (const c of chs) {
+      let v: TxtChapter | undefined;
+      for (const m of volMarks) if (m.start < c.start) v = m;
+        else break;
+      if (!v) continue;
+      c.vol = v.title;
+      if (c.start - v.start < MIN_GAP) c.start = v.start; // 卷题行并入本章开头,不留在上一章尾部
+    }
+    return chs;
+  }
+  const out: TxtChapter[] = [];
+  for (let s = 0, i = 1; s < text.length; i++) {
+    let e = Math.min(s + CHUNK, text.length);
+    if (e < text.length) {
+      const brk = text.lastIndexOf("\n", e);
+      if (brk > s) e = brk + 1;
+    }
+    out.push({ title: `第 ${i} 节`, start: s });
+    s = e;
+  }
+  return out;
+}
+
+export function chapterText(text: string, chapters: TxtChapter[], i: number): string {
+  return text.slice(chapters[i].start, chapters[i + 1]?.start ?? text.length);
+}

frontend/src/lib/encoding.ts

@@ -0,0 +1,12 @@
+// 网络 txt 常是 GBK/GB2312 而服务端一律标 charset=utf-8:先严格试 UTF-8,
+// 失败回退 GB18030(GBK 超集);UTF-16 靠 BOM 识别。纯逻辑,vitest 覆盖。
+export function decodeText(buf: ArrayBuffer): string {
+  const b = new Uint8Array(buf);
+  if (b[0] === 0xff && b[1] === 0xfe) return new TextDecoder("utf-16le").decode(b);
+  if (b[0] === 0xfe && b[1] === 0xff) return new TextDecoder("utf-16be").decode(b);
+  try {
+    return new TextDecoder("utf-8", { fatal: true }).decode(b);
+  } catch {
+    return new TextDecoder("gb18030").decode(b);
+  }
+}

frontend/src/readers/TextReader.tsx

@@ -2,34 +2,57 @@ import DOMPurify from "dompurify";
 import { marked } from "marked";
 import { useEffect, useMemo, useRef, useState } from "react";
 import { apiRaw } from "../api/client";
-import { btn } from "../components/ui";
+import { btn, input } from "../components/ui";
+import { chapterText, splitChapters } from "../lib/chapters";
+import { decodeText } from "../lib/encoding";
 import { useProgressSaver, type ReaderProps } from "../lib/useProgress";
 
-export default function TextReader({ book, initialLocator }: ReaderProps) {
+function useFileText(url: string) {
-  const boxRef = useRef<HTMLDivElement>(null);
-  const saver = useProgressSaver(book.id);
-  const restored = useRef(false);
   const [text, setText] = useState<string | null>(null);
   const [err, setErr] = useState("");
   const [nonce, setNonce] = useState(0);
-
   useEffect(() => {
     let dead = false;
     setText(null);
     setErr("");
-    apiRaw(book.file_url ?? "")
+    apiRaw(url)
-      .then((r) => r.text())
+      .then((r) => r.arrayBuffer())
-      .then((t) => !dead && setText(t))
+      .then((b) => !dead && setText(decodeText(b)))
       .catch((e) => !dead && setErr(e instanceof Error ? e.message : "读取失败"));
     return () => {
       dead = true;
     };
-  }, [book.file_url, nonce]);
+  }, [url, nonce]);
+  return { text, err, retry: () => setNonce((n) => n + 1) };
+}
 
-  const html = useMemo(() => {
+function LoadState({ text, onRetry }: { text: string; onRetry?: () => void }) {
-    if (text == null || book.format !== "md") return null;
+  return (
-    return DOMPurify.sanitize(marked.parse(text, { async: false }));
+    <div className="grid h-full place-items-center p-8 text-center">
-  }, [text, book.format]);
+      <div>
+        {onRetry && <p className="mb-3 text-red-400">{text}</p>}
+        {!onRetry && <p className="text-zinc-500">{text}</p>}
+        {onRetry && (
+          <button className={btn} onClick={onRetry}>
+            重试
+          </button>
+        )}
+      </div>
+    </div>
+  );
+}
+
+export default function TextReader(props: ReaderProps) {
+  return props.book.format === "md" ? <MdView {...props} /> : <TxtView {...props} />;
+}
+
+function MdView({ book, initialLocator }: ReaderProps) {
+  const boxRef = useRef<HTMLDivElement>(null);
+  const saver = useProgressSaver(book.id);
+  const restored = useRef(false);
+  const { text, err, retry } = useFileText(book.file_url ?? "");
+
+  const html = useMemo(() => (text == null ? null : DOMPurify.sanitize(marked.parse(text, { async: false }))), [text]);
 
   useEffect(() => {
     if (restored.current || text == null || !boxRef.current) return;
@@ -49,25 +72,124 @@ export default function TextReader({ book, initialLocator }: ReaderProps) {
     saver.report({ scrollFraction: frac }, frac);
   }
 
-  if (err)
+  if (err) return <LoadState text={err} onRetry={retry} />;
-    return (
+  if (text == null) return <LoadState text="正文加载中…" />;
-      <div className="grid h-full place-items-center p-8 text-center">
-        <div>
-          <p className="mb-3 text-red-400">{err}</p>
-          <button className={btn} onClick={() => setNonce((n) => n + 1)}>
-            重试
-          </button>
-        </div>
-      </div>
-    );
-  if (text == null) return <div className="grid h-full place-items-center text-zinc-500">正文加载中…</div>;
-
   return (
     <div ref={boxRef} onScroll={onScroll} className="h-full overflow-y-auto p-6">
-      {html !== null ? (
+      <article className="md-body mx-auto max-w-2xl text-[15px] leading-7" dangerouslySetInnerHTML={{ __html: html ?? "" }} />
-        <article className="md-body mx-auto max-w-2xl text-[15px] leading-7" dangerouslySetInnerHTML={{ __html: html }} />
+    </div>
+  );
+}
+
+// 整本塞一个 <pre> 会冻死浏览器:按章渲染,一章一个滚动块。
+function TxtView({ book, initialLocator }: ReaderProps) {
+  const boxRef = useRef<HTMLDivElement>(null);
+  const saver = useProgressSaver(book.id);
+  const inited = useRef(false);
+  const restoreFrac = useRef<number | null>(null);
+  const targetCi = useRef(0);
+  const [ci, setCi] = useState(0);
+  const { text, err, retry } = useFileText(book.file_url ?? "");
+
+  const chapters = useMemo(() => (text == null ? null : splitChapters(text)), [text]);
+
+  useEffect(() => {
+    if (inited.current || !chapters) return;
+    inited.current = true;
+    const f = Number(initialLocator?.scrollFraction);
+    const hasF = Number.isFinite(f) && f > 0 && f <= 1;
+    const rawCh = Number(initialLocator?.ch);
+    let idx = 0;
+    if (Number.isFinite(rawCh) && rawCh >= 0 && rawCh < chapters.length) {
+      idx = Math.floor(rawCh);
+      if (hasF) restoreFrac.current = f;
+    } else if (hasF) {
+      const p = f * chapters.length; // 旧版全局分数 → 章节近似定位
+      idx = Math.min(chapters.length - 1, Math.floor(p));
+      restoreFrac.current = p - idx;
+    }
+    if (idx > 0 || restoreFrac.current != null) {
+      targetCi.current = idx;
+      setCi(idx);
+    }
+  }, [chapters, initialLocator]);
+
+  useEffect(() => {
+    const el = boxRef.current;
+    if (!el || !chapters || ci !== targetCi.current) return;
+    if (restoreFrac.current != null) {
+      el.scrollTop = restoreFrac.current * (el.scrollHeight - el.clientHeight);
+      restoreFrac.current = null;
+    } else el.scrollTop = 0;
+  }, [ci, chapters]);
+
+  function goChapter(i: number) {
+    if (!chapters) return;
+    restoreFrac.current = null;
+    setCi(i);
+    saver.report({ ch: i, scrollFraction: 0 }, i / chapters.length);
+  }
+
+  function onScroll() {
+    const el = boxRef.current;
+    if (!el || !chapters) return;
+    const max = el.scrollHeight - el.clientHeight;
+    const frac = max > 0 ? Math.min(1, Math.max(0, el.scrollTop / max)) : 0;
+    saver.report({ ch: ci, scrollFraction: frac }, (ci + frac) / chapters.length);
+  }
+
+  if (err) return <LoadState text={err} onRetry={retry} />;
+  if (text == null || !chapters) return <LoadState text="正文加载中…" />;
+
+  return (
+    <div className="flex h-full flex-col">
+      {chapters.length > 1 && (
+        <div className="flex shrink-0 items-center gap-2 border-b border-zinc-800 px-4 py-2 text-sm">
+          <select className={input + " max-w-64"} value={ci} onChange={(e) => goChapter(Number(e.target.value))}>
+            {(() => {
+              const groups: { vol: string | undefined; items: number[] }[] = [];
+              chapters.forEach((c, i) => {
+                const last = groups[groups.length - 1];
+                if (!last || last.vol !== c.vol) groups.push({ vol: c.vol, items: [i] });
+                else last.items.push(i);
+              });
+              const opt = (i: number) => (
+                <option key={i} value={i}>
+                  {i + 1}. {chapters[i].title}
+                </option>
+              );
+              return groups.length === 1 && !groups[0].vol
+                ? chapters.map((_, i) => opt(i))
+                : groups.map((g, gi) =>
+                    g.vol ? (
+                      <optgroup key={gi} label={g.vol}>
+                        {g.items.map(opt)}
+                      </optgroup>
                     ) : (
-        <pre className="mx-auto max-w-2xl font-sans text-[15px] leading-7 break-words whitespace-pre-wrap">{text}</pre>
+                      g.items.map(opt)
+                    ),
+                  );
+            })()}
+          </select>
+          <span className="ml-auto text-zinc-500">
+            {ci + 1}/{chapters.length}
+          </span>
+        </div>
+      )}
+      <div ref={boxRef} onScroll={onScroll} className="min-h-0 flex-1 overflow-y-auto p-6">
+        <pre className="mx-auto max-w-2xl font-sans text-[15px] leading-7 break-words whitespace-pre-wrap">
+          {chapterText(text, chapters, ci)}
+        </pre>
+      </div>
+      {chapters.length > 1 && (
+        <div className="flex shrink-0 items-center justify-center gap-3 border-t border-zinc-800 px-4 py-2 text-sm">
+          <button className={btn} disabled={ci === 0} onClick={() => goChapter(ci - 1)}>
+            上一章
+          </button>
+          <button className={btn} disabled={ci === chapters.length - 1} onClick={() => goChapter(ci + 1)}>
+            下一章
+          </button>
+        </div>
       )}
     </div>
   );

frontend/test/chapters.test.ts

@@ -0,0 +1,58 @@
+import { expect, it } from "vitest";
+import { chapterText, splitChapters } from "../src/lib/chapters";
+
+const pad = (n: number) => "字".repeat(n);
+
+it("识别中文/英文章节标题,首章前的引子归入「开篇」", () => {
+  const t = `${pad(300)}\n简介正文\n\n第一章 初入江湖\n${pad(500)}\n\n第二章 风起云涌\n${pad(500)}\n\nChapter 3 the end\n${pad(100)}`;
+  const chs = splitChapters(t);
+  expect(chs.map((c) => c.title)).toEqual(["开篇", "第一章 初入江湖", "第二章 风起云涌", "Chapter 3 the end"]);
+  expect(chs[1].start).toBe(t.indexOf("第一章"));
+  expect(chapterText(t, chs, 1)).toMatch(/^第一章 初入江湖/);
+  expect(chapterText(t, chs, chs.length - 1).trim().length).toBeLessThanOrEqual(200 + 15);
+});
+
+it("密集目录行(间隔 < MIN_GAP)被折叠,正文里的真章节仍可导航", () => {
+  const toc = ["第一章 aaa", "第二章 bbb", "第三章 ccc"].map((s) => s + "\n").join("");
+  const t = toc + "\n" + pad(500) + "\n第三章 ccc 正式开讲\n" + pad(500) + "\n第四章 ddd\n" + pad(500);
+  const chs = splitChapters(t);
+  expect(chs.map((c) => c.title)).toEqual(["第一章 aaa", "第三章 ccc 正式开讲", "第四章 ddd"]);
+});
+
+it("无章节标记的长文按段落边界切伪章节,覆盖全文不重叠", () => {
+  const para = pad(2500) + "\n\n";
+  const t = para.repeat(40); // 10 万字
+  const chs = splitChapters(t);
+  expect(chs.length).toBeGreaterThanOrEqual(5);
+  expect(chs[0].title).toBe("第 1 节");
+  expect(chs[0].start).toBe(0);
+  for (let i = 0; i < chs.length; i++) expect(chs[i].start).toBeLessThan(chs[i + 1]?.start ?? t.length);
+  if (chs.length > 1) expect(t[chs[1].start - 1]).toBe("\n"); // 落点在换行后,不切断一行
+  const total = chs.reduce((n, c, i) => n + (chs[i + 1]?.start ?? t.length) - c.start, 0);
+  expect(total).toBe(t.length);
+});
+
+it("短文无标记 → 单节,chapterText 即全文", () => {
+  const t = "hello\nworld";
+  const chs = splitChapters(t);
+  expect(chs).toEqual([{ title: "第 1 节", start: 0 }]);
+  expect(chapterText(t, chs, 0)).toBe(t);
+});
+
+it("卷不是章节边界:只按章切,卷题作分组标签并并入所属章开头", () => {
+  const t =
+    "第一卷 天云世界\n第一章 铜镜\n" + pad(500) + "\n第二章 修炼\n" + pad(500) +
+    "\n\n\n第二卷 仙界\n第三章 飞升\n" + pad(300);
+  const chs = splitChapters(t);
+  expect(chs.map((c) => c.title)).toEqual(["第一章 铜镜", "第二章 修炼", "第三章 飞升"]);
+  expect(chs.map((c) => c.vol)).toEqual(["第一卷 天云世界", "第一卷 天云世界", "第二卷 仙界"]);
+  expect(chs[2].start).toBe(t.indexOf("第二卷 仙界")); // 卷题行从本章开头渲染,而非上一章结尾
+  expect(chapterText(t, chs, 2)).toMatch(/^第二卷 仙界/);
+});
+
+it("只有卷没有章的书:卷即章节", () => {
+  const t = "第一卷 起\n" + pad(600) + "\n第二卷 承\n" + pad(600) + "\n第三卷 转\n" + pad(600);
+  const chs = splitChapters(t);
+  expect(chs.map((c) => c.title)).toEqual(["第一卷 起", "第二卷 承", "第三卷 转"]);
+  expect(chs.every((c) => c.vol === undefined)).toBe(true);
+});

frontend/test/encoding.test.ts

@@ -0,0 +1,23 @@
+import { expect, it } from "vitest";
+import { decodeText } from "../src/lib/encoding";
+
+const u8 = (...rows: number[][]) => new Uint8Array(rows.flat());
+const ab = (v: Uint8Array) => v.slice().buffer;
+
+it("GBK 编码的中文回退 GB18030 正确解码", () => {
+  expect(decodeText(ab(u8([0xd6, 0xd0], [0xce, 0xc4])))).toBe("中文");
+});
+
+it("合法 UTF-8 不被 GBK 路径污染;UTF-8 BOM 被剥掉", () => {
+  expect(decodeText(ab(u8([0xe4, 0xb8, 0xad], [0xe6, 0x96, 0x87])))).toBe("中文");
+  expect(decodeText(ab(u8([0xef, 0xbb, 0xbf], [0xe4, 0xb8, 0xad])))).toBe("中");
+});
+
+it("UTF-16 靠 BOM 识别", () => {
+  expect(decodeText(ab(u8([0xff, 0xfe], [0x2d, 0x4e])))).toBe("中");
+  expect(decodeText(ab(u8([0xfe, 0xff], [0x4e, 0x2d])))).toBe("中");
+});
+
+it("纯 ASCII 原样通过", () => {
+  expect(decodeText(ab(u8([...new TextEncoder().encode("hello\nworld")])))).toBe("hello\nworld");
+});