// ==UserScript== // @name PKU-Thesis-Download 北大论文平台下载工具 // @namespace https://greasyfork.org/zh-CN/scripts/442310-pku-thesis-download // @supportURL https://github.com/xiaotianxt/PKU-Thesis-Download // @homepageURL https://github.com/xiaotianxt/PKU-Thesis-Download // @version 1.3.1 // @description 北大论文平台下载工具，请勿传播下载的文件，否则后果自负。 // @author xiaotianxt // @match http://162.105.134.201/pdfindex* // @match https://drm.lib.pku.edu.cn/pdfindex* // @match https://drm-lib-pku-edu-cn-443.webvpn.bjmu.edu.cn/pdfindex* // @match https://wpn.pku.edu.cn/https/*/pdfindex* // @icon https://www.google.com/s2/favicons?sz=64&domain=pku.edu.cn // @require https://cdnjs.cloudflare.com/ajax/libs/jspdf/2.5.1/jspdf.umd.min.js // @require https://cdnjs.cloudflare.com/ajax/libs/notify/0.4.2/notify.min.js // @license GNU GPLv3 // @grant GM_addStyle // @history 1.2.2 修复了横屏图片的加载样式和pdf渲染样式 // @history 1.2.3 支持北医 Web VPN 系统 // @history 1.2.4 适配限流问题 // @history 1.2.5 适当降低请求频率，避免触发过多限流 // @history 1.2.6 支持北大 Web VPN 系统 // @history 1.3.0 优化图片加载失败重试机制 // @history 1.3.1 恢复重试时的loading动画 // @downloadURL https://update.greasyfork.icu/scripts/442310/PKU-Thesis-Download%20%E5%8C%97%E5%A4%A7%E8%AE%BA%E6%96%87%E5%B9%B3%E5%8F%B0%E4%B8%8B%E8%BD%BD%E5%B7%A5%E5%85%B7.user.js // @updateURL https://update.greasyfork.icu/scripts/442310/PKU-Thesis-Download%20%E5%8C%97%E5%A4%A7%E8%AE%BA%E6%96%87%E5%B9%B3%E5%8F%B0%E4%B8%8B%E8%BD%BD%E5%B7%A5%E5%85%B7.meta.js // ==/UserScript== (function () { "use strict"; class ParallelRateLimiter { constructor(maxParallel) { this.queue = []; this.running = 0; this.maxParallel = maxParallel; } add(fn) { return new Promise((resolve, reject) => { const wrappedFn = async () => { this.running++; try { const result = await fn(); resolve(result); } catch (error) { reject(error); } finally { this.running--; this.runNext(); } }; if (this.running < this.maxParallel) { wrappedFn(); } else { this.queue.push(wrappedFn); } }); } runNext() { if (this.queue.length > 0 && this.running < this.maxParallel) { const nextFn = this.queue.shift(); if (nextFn) { nextFn(); } } } } async function retry(fn, retries = 3, initialDelay = 1000) { let attempt = 0; while (true) { try { return await fn(); } catch (error) { attempt++; if (attempt >= retries) { console.error(`Failed after ${retries} attempts`); throw error; } // 计算指数退避延迟时间: initialDelay * 2^attempt + 随机抖动 const delay = initialDelay * Math.pow(2, attempt) + Math.random() * 1000; console.warn(`Attempt ${attempt} failed. Retrying in ${Math.round(delay)}ms...`); await new Promise(resolve => setTimeout(resolve, delay)); } } } const limiter = new ParallelRateLimiter(3); const print = (...args) => console.log("[PKU-Thesis-Download]", ...args); const OPTIMIZATION = "pku_thesis_download.optimization"; const fid = $("#fid").val(); const totalPage = parseInt($("#totalPages").html().replace(/ \/ /, "")); const baseUrl = `/jumpServlet?fid=${fid}`; const msgBox = initUI(); const isWPN = location.href.includes('wpn.pku.edu.cn') if (localStorage.getItem(OPTIMIZATION) === "true" || !localStorage.getItem(OPTIMIZATION)) { optimizeImgLoading(); } function initUI() { // 下载按钮 const downloadButton = document.querySelector("#thumbtab").cloneNode(true); downloadButton.innerHTML = `
下载 `; document.querySelector("#btnList").appendChild(downloadButton); downloadButton.addEventListener("click", download); // 论文加载优化 const optimizeImg = document.querySelector("#thumbtab").cloneNode(true); optimizeImg.innerHTML = ` `; optimizeImg.querySelector("input").checked = localStorage.getItem(OPTIMIZATION) === "true" || localStorage.getItem(OPTIMIZATION) === null; optimizeImg.addEventListener("click", (e) => { const checked = e.target.checked; localStorage.setItem(OPTIMIZATION, checked); if (checked) { optimizeImgLoading(); } }); document.querySelector("#btnList").appendChild(optimizeImg); GM_addStyle(` .loadingBg { display: flex; justify-content: center; align-items: center; } `); const observer = new MutationObserver((mutationsList) => { for (let mutation of mutationsList) { if (mutation.type === 'childList') { mutation.addedNodes.forEach((node) => { if (node.nodeName === 'IMG' && node.parentElement.classList.contains('loadingBg')) { node.addEventListener('load', function () { const img = node; if (img.naturalWidth > img.naturalHeight) { // 横向图片 img.style.height = 'min(100%, 90vw / 1.414)'; img.style.width = 'auto'; } }); } }); } } }); observer.observe(document.querySelector(".jspPane-scroll"), { childList: true, subtree: true }); // msgBox const msgBox = downloadButton.querySelector("span"); return msgBox; } function processWPN(url) { const baseWPN = location.href.split('pdfindex')[0]; return `${baseWPN}pdfboxServlet` + url.split('pdfboxServlet')[1] + '&vpn=1' } async function download(e) { e.preventDefault(); e.target.disabled = true; await solveSrc().then(solveImg).then(solvePDF); e.target.disabled = false; } /** * 解析pdf图片链接 */ async function solveSrc() { async function downloadSrcInfo(url) { const res = await fetch(url); if (!res.ok) { throw new Error(`HTTP error! status: ${res.status}`); } const json = await res.json(); finished += 2; msgBox.innerHTML = `${finished}/${totalPage}`; return json.list; } let finished = 0; const tasks = []; for (let page = 0; page < totalPage; page += 2) { const url = `${baseUrl}&page=${page}`; tasks.push(() => retry(async () => downloadSrcInfo(url))); } const results = await Promise.all(tasks.map(task => limiter.add(task))); return results.flat(); // 假设我们想要一个扁平化的结果数组 } /** * 下载图片 */ async function solveImg(urls) { let numFinished = 0; async function downloadPdf(url) { if (isWPN) { url = processWPN(url) } return fetch(url) .then((res) => res.blob()) .then((blob) => { const reader = new FileReader(); reader.readAsDataURL(blob); return new Promise((resolve, reject) => { reader.onloadend = () => { const base64 = reader.result; const img = new Image(); img.src = base64; img.onload = () => { const orientation = img.width > img.height ? "landscape" : "portrait"; resolve({ base64, orientation }); numFinished++; msgBox.innerHTML = numFinished + "/" + numTotal; }; img.onerror = () => { console.error("Failed to load image", url); reject(null); } }; }); }); } // remove duplicated const map = new Map(urls.flat().map((item) => [item.id, item.src])); // assert that all pages are loaded if (map.size !== totalPage) { const missing = Array.from({ length: totalPage }, (_, i) => i + 1).filter((i) => !map.has(`${i}`)); alert(`部分页面没有加载出来，请联系开发者。\n缺少：${missing.join(",")}`); } // sort and clear index const sortedUrls = [...map.entries()] .sort((a, b) => a[0] - b[0]) .map((item) => item[1]); // download images const tasks = []; const numTotal = sortedUrls.length; sortedUrls.forEach((url) => { tasks.push(async () => await retry(async () => await downloadPdf(url))); }); return Promise.all(tasks.map(task => limiter.add(task))); } /** * PDF生成与保存 * @param {Array} base64s - 包含图片base64数据和方向信息的数组 */ async function solvePDF(base64s) { msgBox.innerHTML = "拼接中"; const doc = new jspdf.jsPDF({ format: 'a4', orientation: 'portrait' }); for (let i = 0; i < base64s.length; i++) { const { base64, orientation } = base64s[i]; const isLandscape = orientation === "landscape"; // 根据方向设置不同的尺寸 if (isLandscape) { doc.addImage(base64, "JPEG", 0, 0, 297, 210); } else { doc.addImage(base64, "JPEG", 0, 0, 210, 297); } // 如果不是最后一页，添加新页面 if (i + 1 < base64s.length) { doc.addPage("a4", base64s[i + 1].orientation); } } msgBox.innerHTML = "保存中"; doc.save(document.title + ".pdf"); msgBox.innerHTML = "完成！"; } /** * 优化图片加载策略 * 实现懒加载、预加载和加载失败自动重试机制 */ async function optimizeImgLoading() { /** * 为指定页面加载图片 * @param {Element} element - 页面元素 * @param {IntersectionObserver} observer - 观察器实例 */ function loadImgForPage(element, observer) { const pages = document.getElementsByClassName('fwr_page_box'); const index = Array.from(pages).indexOf(element) + 1; observer.unobserve(element); // 每三页触发一次预加载 if (index % 3 !== 1) return; print(`load page ${index + 3} - ${index + 5}.`); omg(index + 3); // 提前加载3页 } /** * 设置图片加载监控和自动重试机制 */ function setupImgLoadMonitor() { const imgObserver = new MutationObserver(mutations => { mutations.forEach(mutation => { if (mutation.type !== 'childList') return; mutation.addedNodes.forEach(node => { // 筛选需要监控的图片元素 const isTargetImage = node.nodeName === 'IMG' && node.classList.contains('fwr_page_bg_image') && node.parentElement?.classList.contains('loadingBg'); if (!isTargetImage) return; // 保存原始src用于重试 const originalSrc = node.src; node.setAttribute('data-original-src', originalSrc); // 延迟检查图片加载状态 setTimeout(() => checkAndRetryIfNeeded(node), 1000); }); }); }); /** * 检查图片加载状态并在需要时重试 * @param {HTMLImageElement} img - 图片元素 * @param {number} retryCount - 当前重试次数 */ const checkAndRetryIfNeeded = (img, retryCount = 0) => { const maxRetries = 10; // 图片已成功加载 if (img.complete && img.naturalWidth > 0) { return; } // 达到最大重试次数 if (retryCount >= maxRetries) { console.error(`[PKU-Thesis-Download] Failed to load image after ${maxRetries} attempts: ${img.id}`); return; } // 使用指数退避算法计算下次重试延迟 const baseDelay = 1000 * Math.pow(2, retryCount); const jitter = Math.random() * 1000; const delay = baseDelay + jitter; console.warn( `[PKU-Thesis-Download] Image not loaded properly, retry ${retryCount + 1} of ${maxRetries} ` + `in ${Math.round(delay)}ms: ${img.id}` ); // 延迟后重试加载 setTimeout(() => { // 清除错误状态 img.style.display = ''; // 重新显示loading动画（在父元素loadingBg上） const loadingBgParent = img.closest('.loadingBg'); if (loadingBgParent) { // 确保loadingBg显示 loadingBgParent.style.display = 'block'; } // 将图片设置为透明，这样可以看到背景的loading动画 img.style.opacity = '0'; // 当图片加载成功时恢复透明度 img.onload = function() { img.style.opacity = '1'; }; // 添加时间戳参数避免缓存 const timestamp = new Date().getTime(); const originalSrc = img.getAttribute('data-original-src'); const separator = originalSrc.includes('?') ? '&' : '?'; const newSrc = `${originalSrc}${separator}_retry=${timestamp}`; // 重新设置src触发加载 img.src = newSrc; // 安排下一次检查 setTimeout(() => checkAndRetryIfNeeded(img, retryCount + 1), 1000); }, delay); }; // 观察整个文档的DOM变化 imgObserver.observe(document.body, { childList: true, subtree: true }); } // 创建交叉观察器用于懒加载 const observer = new IntersectionObserver( (entries, observer) => { entries.forEach(entry => { if (entry.isIntersecting) { loadImgForPage(entry.target, observer); } }); }, { root: document.querySelector('#jspPane'), rootMargin: '0px', threshold: 0 } ); // 选择性地观察页面容器 const pages = document.querySelectorAll('.fwr_page_box:nth-child(3n+1)'); pages.forEach(page => observer.observe(page)); // 启动图片加载监控 setupImgLoadMonitor(); } })();