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。
// ==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 1.3.0
// @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
// ==/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 = `
<div class="panel-bg" style="background: url("data:image/png;base64,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") center center no-repeat;"></div>
<span class="panel-name">下载</span>
`;
document.querySelector("#btnList").appendChild(downloadButton);
downloadButton.addEventListener("click", download);
// 论文加载优化
const optimizeImg = document.querySelector("#thumbtab").cloneNode(true);
optimizeImg.innerHTML = `
<input type="checkbox" id="optimizeImg" name="optimizeImg" value="true"><label for="optimizeImg">优化加载</label>
`;
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: ${img.id}`
);
// 延迟后重试加载
setTimeout(() => {
// 清除错误状态
img.style.display = '';
// 添加时间戳参数避免缓存
const timestamp = new Date().getTime();
const originalSrc = img.getAttribute('data-original-src');
const separator = originalSrc.includes('?') ? '&' : '?';
const newSrc = `${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();
}
})();