feat: 发布 v2.1.0 开放书源扩展

src/sources/openstax.js

@@ -0,0 +1,180 @@
+const { fetchJson, clampPage, stripTags } = require('./http');
+
+const BASE = 'https://openstax.org';
+const CATALOG_URL = `${BASE}/apps/cms/api/books`;
+const DETAIL_BASE = `${BASE}/apps/cms/api/v2/pages`;
+const PAGE_SIZE = 20;
+const CATALOG_TTL = 30 * 60 * 1000;
+
+let catalogPromise = null;
+let catalogAt = 0;
+
+function getJson(url) {
+  return fetchJson(url);
+}
+
+async function loadCatalog() {
+  const now = Date.now();
+  if (catalogPromise && now - catalogAt < CATALOG_TTL) return catalogPromise;
+  const promise = getJson(CATALOG_URL).then((j) => {
+    if (!j || !Array.isArray(j.books)) throw new Error('OpenStax 返回了无法识别的书目');
+    return j.books.filter((b) => b && b.id && b.book_state === 'live');
+  });
+  catalogPromise = promise;
+  catalogAt = now;
+  try {
+    return await promise;
+  } catch (e) {
+    if (catalogPromise === promise) {
+      catalogPromise = null;
+      catalogAt = 0;
+    }
+    throw e;
+  }
+}
+
+function validateId(postId) {
+  const id = String(postId || '');
+  if (!/^\d+$/.test(id)) throw new Error('无效的 OpenStax ID');
+  return id;
+}
+
+function pageUrl(book) {
+  const slug = String(book && book.slug || '').replace(/^\/+/, '');
+  return slug ? `${BASE}/details/${slug}` : `${BASE}/subjects`;
+}
+
+function toItem(book) {
+  return {
+    postId: String(book.id),
+    title: book.title || '(无标题)',
+    cover: book.cover_url || '',
+    date: '',
+    url: pageUrl(book),
+    subtitle: (book.subjects || []).slice(0, 3).join(' · ')
+  };
+}
+
+function pack(books, page) {
+  const start = (page - 1) * PAGE_SIZE;
+  return {
+    items: books.slice(start, start + PAGE_SIZE).map(toItem),
+    maxPage: Math.max(1, Math.ceil(books.length / PAGE_SIZE)),
+    page
+  };
+}
+
+function matches(book, keyword) {
+  const tokens = String(keyword || '').trim().toLocaleLowerCase().split(/\s+/).filter(Boolean);
+  if (!tokens.length) return true;
+  const text = [
+    book.title,
+    ...(book.subjects || []),
+    ...(book.subject_categories || [])
+  ].filter(Boolean).join(' ').toLocaleLowerCase();
+  return tokens.every((token) => text.includes(token));
+}
+
+function authorsOf(book) {
+  return (book.authors || []).map((author) => {
+    if (typeof author === 'string') return author;
+    return author && author.value && author.value.name
+      ? author.value.name
+      : (author && author.name) || '';
+  }).filter(Boolean);
+}
+
+function subjectNames(value) {
+  const items = Array.isArray(value) ? value : (value ? [value] : []);
+  return items.map((item) => (
+    typeof item === 'string' ? item : (item && (item.subject_name || item.name)) || ''
+  )).filter(Boolean);
+}
+
+async function bookDetail(postId) {
+  const id = validateId(postId);
+  const book = await getJson(`${DETAIL_BASE}/${id}/`);
+  if (!book || !book.id) throw new Error('未找到该 OpenStax 教材');
+  return book;
+}
+
+function detailUrl(book) {
+  return (book.meta && book.meta.html_url) || `${BASE}/details/books/${book.meta && book.meta.slug || book.id}`;
+}
+
+function licenseLabel(book) {
+  return [book.license_name, book.license_version].filter(Boolean).join(' ');
+}
+
+function safeName(title) {
+  return String(title || 'OpenStax 教材').replace(/[\\/:*?"<>|]/g, '_').slice(0, 80);
+}
+
+module.exports = {
+  id: 'openstax',
+  name: 'OpenStax 开放教材',
+  supportsSearch: true,
+
+  async list(page) {
+    page = clampPage(page);
+    return pack(await loadCatalog(), page);
+  },
+
+  async search(keyword, page) {
+    page = clampPage(page);
+    const books = (await loadCatalog()).filter((book) => matches(book, keyword));
+    return pack(books, page);
+  },
+
+  async detail(postId) {
+    const book = await bookDetail(postId);
+    const subjects = [
+      ...subjectNames(book.book_subjects),
+      ...subjectNames(book.book_categories)
+    ];
+    return {
+      postId: String(book.id),
+      title: book.title || '(无标题)',
+      cover: book.cover_url || '',
+      authors: authorsOf(book),
+      date: String(book.publish_date || '').slice(0, 10),
+      tags: [
+        ...subjects.slice(0, 4).map((subject) => `主题：${subject}`),
+        licenseLabel(book) ? `许可：${licenseLabel(book)}` : '',
+        book.digital_isbn_13 ? `ISBN：${book.digital_isbn_13}` : ''
+      ].filter(Boolean),
+      brief: stripTags(book.description || ''),
+      url: detailUrl(book),
+      links: [
+        { name: 'OpenStax 页', url: detailUrl(book) },
+        ...(book.webview_link || book.webview_rex_link
+          ? [{ name: '在线阅读', url: book.webview_link || book.webview_rex_link }]
+          : [])
+      ]
+    };
+  },
+
+  async download(postId) {
+    const book = await bookDetail(postId);
+    const files = [];
+    const seen = new Set();
+    for (const [url, label] of [
+      [book.pdf_url, 'PDF'],
+      [book.high_resolution_pdf_url, '高清 PDF']
+    ]) {
+      if (!url || seen.has(url)) continue;
+      seen.add(url);
+      files.push({
+        name: `${safeName(book.title)}${label === '高清 PDF' ? '-高清' : ''}.pdf`,
+        link: url,
+        format: 'PDF'
+      });
+    }
+    const links = [{ name: 'OpenStax 页', url: detailUrl(book) }];
+    if (book.webview_link || book.webview_rex_link) {
+      links.push({ name: '在线阅读', url: book.webview_link || book.webview_rex_link });
+    }
+    if (book.license_url) links.push({ name: '许可说明', url: book.license_url });
+    return { files, links };
+  }
+};