东立漫画下载

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东立漫画下载

自动下载电子书城的漫画
目前为 2022-12-21 提交的版本，查看最新版本。
换行
// ==UserScript==
// @name         东立漫画下载
// @namespace    http://tampermonkey.net/
// @version      0.2
// @description  自动下载电子书城的漫画
// @author       shadows
// @license      MIT License
// @match        https://ebook.tongli.com.tw/reader/FireBase2.html?bookID=*
// @icon         https://ebook.tongli.com.tw/images/logo_small.jpg
// @grant        none
// @require      https://gcore.jsdelivr.net/npm/[email protected]/dist/jszip.min.js
// @require      https://gcore.jsdelivr.net/npm/[email protected]/dist/FileSaver.min.js
// @run-at       document-end
// ==/UserScript==
"use strict";
const buttonCSS = `display: inline-block;
    background: linear-gradient(135deg, #6e8efb, #a777e3);
    color: white;
    padding: 3px 3px;
    margin: 4px 0px;
    text-align: center;
    border-radius: 3px;
    border-width: 0px;
    position: fixed;
    right: 0px;
    bottom: 0px;
    z-index: 99`;

addButton()

function addButton() {
    let button = document.createElement("button");
    button.classList.add("download-button");
    button.textContent = "Download";
    button.style.cssText = buttonCSS;
    button.onclick = clickButton;
    document.body.prepend(button);
}

async function clickButton(event) {
    event.stopPropagation();
    event.preventDefault();
    while (localStorage.getItem("Pages") == null) {
        await new Promise(r => setTimeout(r, 1000));
    }
    const name = document.title;
    const rawData = JSON.parse(localStorage.getItem("Pages"));
    const targetLength = rawData.length.toString().length;
    let imagesData = [];
    let zip = new JSZip();
    for (let i of rawData) {
        imagesData.push({
            filename: `${i.PageNumber.toString().padStart(targetLength,'0')}.jpg`,
            url: i.ImageURL,
            zip: zip,
        })
    }
    await asyncPool(10, imagesData, imageWorker);
    zip.generateAsync({ type: "blob", base64: true }).then(content => saveAs(content, `${name}.zip`));
}

async function imageWorker(item) {
    let image = await fetch(item.url).then(res => res.blob());
    console.log(`${item.filename} have downloaded.`);
    item.zip.file(item.filename, image);
}

/**
 * @param poolLimit 并发控制数 (>= 1)
 * @param array 参数数组
 * @param iteratorFn 异步任务，返回 promise 或是 async 方法
 * https://www.luanzhuxian.com/post/60c2c548.html
 */
function asyncPool(poolLimit, array, iteratorFn) {
    let i = 0
    const ret = [] // Promise.all(ret) 的数组
    const executing = []
    const enqueue = function() {
        // array 遍历完，进入 Promise.all 流程
        if (i === array.length) {
            return Promise.resolve()
        }

        // 每调用一次 enqueue，就初始化一个 promise，并放入 ret 队列
        const item = array[i++]
        const p = Promise.resolve().then(() => iteratorFn(item, array))
        ret.push(p)

        // 插入 executing 队列，即正在执行的 promise 队列，并且 promise 执行完毕后，会从 executing 队列中移除
        const e = p.then(() => executing.splice(executing.indexOf(e), 1))
        executing.push(e)

        // 每当 executing 数组中 promise 数量达到 poolLimit 时，就利用 Promise.race 控制并发数，完成的 promise 会从 executing 队列中移除，并触发 Promise.race 也就是 r 的回调，继续递归调用 enqueue，继续 加入新的 promise 任务至 executing 队列
        let r = Promise.resolve()
        if (executing.length >= poolLimit) {
            r = Promise.race(executing)
        }

        // 递归，链式调用，直到遍历完 array
        return r.then(() => enqueue())
    }

    return enqueue().then(() => Promise.all(ret))
}