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Pixiv novel to Epub

Download pixiv novels in Epub format

/* eslint-disable no-multi-spaces */
/* eslint-disable no-return-assign */

// ==UserScript==
// @name               Pixiv novel to Epub
// @name:zh-CN         Pixiv小说Epub合成器
// @name:en            Pixiv novel to Epub
// @namespace          PY-DNG userscripts
// @version            0.1.6.1
// @description        Download pixiv novels in Epub format
// @description:zh-CN  以Epub格式下载Pixiv小说
// @description:en     Download pixiv novels in Epub format
// @author             PY-DNG
// @license            GPL-3.0-or-later
// @match              *://www.pixiv.net/*
// @match              *://pixiv.net/*
// @connect            pximg.net
// @require            https://update.greasyfork.org/scripts/456034/1348286/Basic%20Functions%20%28For%20userscripts%29.js
// @require            data:application/javascript,window.setImmediate%20%3D%20window.setImmediate%20%7C%7C%20((f%2C%20...args)%20%3D%3E%20window.setTimeout(()%20%3D%3E%20f(args)%2C%200))%3B
// @require            https://fastly.jsdelivr.net/npm/jszip@3.10.1/dist/jszip.min.js
// @require            https://fastly.jsdelivr.net/npm/ejs@3.1.9/ejs.min.js
// @require            https://fastly.jsdelivr.net/npm/jepub@2.1.4/dist/jepub.min.js
// @icon               data:image/png;base64,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
// @grant              GM_xmlhttpRequest
// @grant              GM_registerMenuCommand
// @run-at             document-start
// ==/UserScript==

// @require            https://fastly.jsdelivr.net/npm/setimmediate@1.0.5/setImmediate.min.js
// @require            https://fastly.jsdelivr.net/npm/jepub@2.1.4/dist/jepub.min.js
// @require            https://fastly.jsdelivr.net/npm/ejs@3.1.9/ejs.min.js
// @require            https://fastly.jsdelivr.net/npm/jszip@3.10.1/dist/jszip.min.js

/* global LogLevel DoLog Err $ $All $CrE $AEL $$CrE addStyle detectDom destroyEvent copyProp copyProps parseArgs escJsStr replaceText getUrlArgv dl_browser dl_GM AsyncManager queueTask testChecker registerChecker loadFuncs */
/* global jEpub, JSZip, ejs */

let PixivAPI = (function() {
	queueTask.GM_xmlhttpRequest = {
		sleep: 200,
		max: 10
	};

	return {
		get, safeGet, utils: { toAbsURL, toSearch, queueTask },

		// https://www.pixiv.net/ajax/novel/18673574
		novel: id => safeGet(`/ajax/novel/${id}`),

		// https://www.pixiv.net/ajax/novel/7522350/insert_illusts?id%5B%5D=60139778-1&lang=zh&version=1efff679631a40a674235820806f7431d67065d9
		insert_illusts: (novel_id, illust_ids, lang='zh') => {
			const url = `/ajax/novel/${novel_id}/insert_illusts`;
			const query = { lang };
			if (Array.isArray(illust_ids)) {
				for (let i = 0; i < illust_ids.length; i++) {
					const id = illust_ids[i];
					query[`id[${i}]`] = id;
				}
			} else {
				query[`id[]`] = illust_ids;
			}
			return safeGet(url, query);
		},

		// https://www.pixiv.net/ajax/novel/series/9649276?lang=zh&version=a48f2f681629909b885608393916b81989accf5b
		// 'version' removed due to unspecified meaning
		series: (id, lang='zh') => safeGet(`/ajax/novel/series/${id}`, { id, lang }),

		// https://www.pixiv.net/ajax/novel/series_content/9649276?limit=30&last_order=0&order_by=asc
		series_content: (id, limit=30, last_order=0, order_by='asc') => safeGet(`/ajax/novel/series_content/${id}`, { limit, last_order, order_by }),
	};

	function safeGet() {
		return queueTask(() => get.call(this, ...arguments), 'GM_xmlhttpRequest');
	}

	function get(url, params, responseType='json', retry=2) {
		return new Promise((resolve, reject) => {
			GM_xmlhttpRequest({
				method: 'GET', responseType,
				headers: {
					Referer: /^(www\.)?pixiv\.net$/.test(location.host) ? location.href : 'https://www.pixiv.net/'
				},
				url: toAbsURL(url, params),
				onload: async res => res.status === 200 && (responseType !== 'json' || res.response?.error === false) ? resolve(res.response) : checkRetry(res),
				onerror: checkRetry
			});

			async function checkRetry(err) {
				retry-- > 0 ? resolve(await get(url, params, responseType, retry)) : reject(err);
			}
		});
	}

	function toAbsURL(pathname, searchOptions) {
		return new URL(pathname, `https://www.pixiv.net/`).href + (searchOptions ? `?${toSearch(searchOptions)}` : '');
	}

	function toSearch(options) {
		return new URLSearchParams(options).toString()
	}
}) ();

(async function __MAIN__() {
    'use strict';

	const CONST = {
		TextAllLang: {
			DEFAULT: 'zh-CN',
			'zh-CN': {
				DownloadEpub: '下载当前小说Epub',
				DownloadEpub_Short: '下载Epub',
				DownloadEpub_Progress: 'Epub (C/A)',
				DownloadComplete: 'Epub下载完成'
			}
		},
		GFURL: 'https://greasyfork.org/scripts/483999',
		GFAuthorURL: 'https://greasyfork.org/users/667968'
	};

	// Init language
	const i18n = Object.keys(CONST.TextAllLang).includes(navigator.language) ? navigator.language : CONST.TextAllLang.DEFAULT;
	CONST.Text = CONST.TextAllLang[i18n];

	// @require fallbacks
	await Promise.all([
		{ missing: typeof setImmediate === 'undefined', src: 'https://fastly.jsdelivr.net/npm/setimmediate@1.0.5/setImmediate.min.js' },
		{ missing: typeof JSZip === 'undefined', src: 'https://fastly.jsdelivr.net/npm/jszip@3.10.1/dist/jszip.min.js' },
		{ missing: typeof ejs === 'undefined', src: 'https://fastly.jsdelivr.net/npm/ejs@3.1.9/ejs.min.js' },
		{ missing: typeof jEpub === 'undefined', src: 'https://fastly.jsdelivr.net/npm/jepub@2.1.4/dist/jepub.min.js' }
	].filter(script => script.missing).map(src => new Promise((resolve, reject) => document.head.appendChild($$CrE({
		tagName: 'script',
		props: { src },
		listeners: [
			['load', resolve],
			['error', reject]
		]
	})))));

	// Progress
	const progress = {
		__finished: true, // {boolean} All tasks finished
		__cur: 0,         // {number}  current task number
		__all: 0,         // {number}  all tasks count
		__listeners: {},
		__id: 0,

		start() {
			this.__finished = false;
			this.__cur = 0;
			this.__all = 0;
			Object.values(this.__listeners).forEach(l => l(this.__cur, this.__all, this.__finished));
		},

		finish() {
			this.__finished = true;
			Object.values(this.__listeners).forEach(l => l(this.__cur, this.__all, this.__finished));
		},

		update(cur, all=false) {
			this.__cur = cur;
			all !== false && (this.__all = all);
			Object.values(this.__listeners).forEach(l => l(cur, all, this.__finished));
		},

		listen(l) {
			const id = this.__id++;
			this.__listeners[id] = l;
			return id;
		},

		remove(id) {
			delete this.__listeners[id]
		},

		get finished() {
			return this.__finished;
		},
		get cur() {
			return this.__cur;
		},
		get all() {
			return this.__all;
		},
		get listeners() {
			return this.__listeners;
		}
	};

	// User Interface
	GM_registerMenuCommand(CONST.Text.DownloadEpub, downloadEpub);
	loadFuncs([{
		func: () => {
			detectDom({
				selector: 'main>section section',
				callback: section => {
					if (!testChecker({
						type: 'regpath',
						value: [
							/^\/novel\/show\.php$/,
							/^\/novel\/series\/\d+$/
						]
					})) { return; }

					const toolbar = section;
					const dlDiv = makeDownloadButton();
					toolbar.appendChild(dlDiv);
				}
			});

			function makeDownloadButton() {
				const BUTTON = '<svg class="epub-download-svg" viewBox="0 0 32 32" width="32" height="32">\n            <mask id="mask">\n                <rect x="0" y="0" width="32" height="32" fill="white"></rect>\n                <path d="M21.358 6.7v6.39H27L16 25.7 5 13.09h5.642V6.7z"></path>\n            </mask>\n            <path d="M10.64 5.1c-1.104 0-2 .716-2 1.6v4.8H5c-.745 0-1.428.332-1.773.86s-.294 1.167.133 1.656l11 12.61c.374.43.987.685 1.64.685s1.266-.256 1.64-.685l11-12.61c.426-.49.477-1.127.133-1.656S27.745 11.5 27 11.5h-3.644V6.7c-.001-.883-.895-1.6-2-1.6z" mask="url(#mask)"></path>\n        </svg>';
				const STYLE = '.epub-download { margin-right: 20px; line-height: 32px; font-weight: 700; cursor: pointer; padding: 0px; background: none; border: none; } .epub-download-button { display: inline-block; padding: 0; color: inherit; background: none; height: 32px; line-height: 32px; border: none; font-weight: 700; cursor: pointer; } .epub-download-svg { vertical-align: middle; overflow: visible !important; margin-right: 4px; width: 12px; font-size: 0; -webkit-transition: fill .2s; transition: fill .2s; fill: currentColor; } .epub-download-span { vertical-align: middle; }';
				addStyle(STYLE, 'novel-epub-download');

				const div = $$CrE({
					tagName: 'div',
					classes: 'epub-download',
					//listeners: [['click', e => download]]
				});
				const button = $$CrE({
					tagName: 'button',
					classes: 'epub-download-button',
					props: { innerHTML: BUTTON }
				});
				const span = $$CrE({
					tagName: 'span',
					classes: 'epub-download-span',
					props: { innerText: CONST.Text.DownloadEpub_Short }
				});
				$AEL(div, 'click', download);
				button.appendChild(span);
				div.appendChild(button);
				return div;

				function download() {
					if (!progress.finished) { return; }
					const listernerID = progress.listen((cur, all, finished) => {
						if (finished) {
							span.innerText = CONST.Text.DownloadComplete;
							progress.remove(listernerID);
						} else {
							const text = replaceText(CONST.Text.DownloadEpub_Progress, { C: cur, A: all });
							span.innerText = text;
						}
					})
					downloadEpub();
				}
			}
		}
	}])

	function downloadEpub() {
		const pathname = location.pathname;

		// Novel series
		// https://www.pixiv.net/novel/series/9649276
		/^\/novel\/series\/\d+$/.test(pathname) && downloadSeries();

		// Novel
		// https://www.pixiv.net/novel/show.php?id=18673574
		/^\/novel\/show\.php$/.test(pathname) && downloadNovel();
	}

	async function downloadSeries() {
		DoLog('Start download series');
		progress.start();

		progress.update(1, 5);
		const id = location.pathname.split('/').pop();
		const epub = new jEpub();

		// Get series data
		const series = (await PixivAPI.series(id)).body;
		await initEpub(epub, series);

		// List all novels
		progress.update(2, 5);
		const promises = [];
		for (let index = 0; index < series.total; index += 30) {
			const promise = PixivAPI.series_content(id, 30, index);
			promises.push(promise);
		}
		const list = (await Promise.all(promises)).reduce((l, json) => ((l.push(...json.body.page.seriesContents), l)), []);
		DoLog(list);

		progress.update(3, 5);
		const novel_datas = await Promise.all(list.map(async novel => (await PixivAPI.novel(novel.id)).body));
		DoLog(novel_datas);

		/* Now loading chapter and adding loaded chapter has been separated, use Promise.all to speed up the process
		// Add chapters one by one
		// Do not use promise.all, because that will break the order
		for (const data of novel_datas) {
			await addChapter(epub, data);
		}
		//await Promise.all(novel_datas.map(async data => await addChapter(epub, data)));
		*/
		// Load all chapters asynchronously and Add them to epub at once
		progress.update(4, 5);
		const chapters = await Promise.all(novel_datas.map(data => loadChapter(epub, data)));
		chapters.forEach(chapter => addLoaded(epub, chapter));
		DoLog(chapters);
		DoLog('Saving Epub');

		progress.update(5, 5);
		saveEpub(epub, series.title + '.epub', () => progress.finish());
	}

	async function downloadNovel() {
		DoLog('Start download novel');
		progress.start();
		progress.update(1, 2);

		const id = getUrlArgv('id');
		const json = await PixivAPI.novel(id);
		const data = json.body;

		const epub = new jEpub();
		await Promise.all([initEpub(epub, data), addChapter(epub, data)]);
		progress.update(2, 2);

		saveEpub(epub, data.title + '.epub', () => progress.finish());
	}

	// Compatible with PixivAPI.novel / PixivAPI.series
	async function initEpub(epub, data) {
		epub.init({
			i18n: 'en',
			title: data.title,
			author: data.userName,
			publisher: '',
			description: data.description || data.caption || '',
			tags: Array.isArray(data.tags) ? data.tags : data.tags.tags.map(tag => tag.tag)
		});
		epub.date(new Date(data.uploadDate || data.lastPublishedContentTimestamp));
		epub.notes(`EPUB generated from: <a href="${htmlEncode(location.href)}" title="${htmlEncode(data.extraData.meta.title)}">${htmlEncode(location.href)}</a></br>By <a href="${htmlEncode(CONST.GFURL)}">${htmlEncode(GM_info.script.name)}</a> author <a href="${htmlEncode(CONST.GFAuthorURL)}">${htmlEncode(GM_info.script.author)}</a></br></br>Copyright belongs to the article author. Please comply with relevant legal requirements while reading and distributing this file.`);

		const coverUrl = data.coverUrl || data.cover.urls.original;
		const cover = await PixivAPI.safeGet(coverUrl, null, 'blob');
		epub.cover(cover);

		return epub;
	}

	// Load chapter assets and generate { title, content } (that ready to epub.add) which is called a 'chapter'
	async function loadChapter(epub, data) {
		let content = data.content;

		// Load images
		const imagePromises = [];
		content = content.replace(/\[uploadedimage:([\d\-]+)\]/g, (match_str, id) => {
			const url = data.textEmbeddedImages[id].urls.original;
			const promise = PixivAPI.safeGet(url, null, 'blob').then(blob => epub.image(blob, id));//.catch(err => );
			imagePromises.push(promise);
			return `\n<%= image[${id}] %>\n`;
		});
		const illusts = Array.from(new Set( [...content.matchAll(/\[pixivimage:([\d\-]+)\]/g)] ));
		if (illusts.length) {
			const illustsJson = await PixivAPI.insert_illusts(data.id, illusts.map(match => match[1]));
			illusts.forEach(illust => {
				const id = illust[1];
				if (illustsJson.body[id].visible) {
					const url = illustsJson.body[id].illust.images.original;
					const promise = PixivAPI.safeGet(url, null, 'blob').then(blob => epub.image(blob, id));//.catch(err => );
					imagePromises.push(promise);
					content = content.replaceAll(illust[0], `\n<%= image[${escJsStr(id)}] %>\n`);
				}
			});
		}
		await Promise.all(imagePromises);

		// Parse '[[rb:久世彩葉 > くぜ いろは]]' // 10618179
		content = content.replace(/\[\[rb:([^\[\]]+) *> *([^\[\]]+)\]\]/g, (match_str, main, desc) => {
			return `<ruby>${htmlEncode(main)}<rp>(</rp><rt>${htmlEncode(desc)}</rt><rp>)</rp></ruby>`;
		});

		// Parse '[chapter:【プロローグ】]' // 21893883
		content = content.replace(/\[chapter: *([^\]]+)\]/g, (match_str, chapterName) => {
			return `<h2>${chapterName}</h2>`;
		});

		// Parse '[[jumpuri:捕虜の待遇に関する千九百四十九年八月十二日のジュネーヴ条約(第三条約)【日本国防衛省ホームページより】 > https://www.mod.go.jp/j/presiding/treaty/geneva/geneva3.html]]' // 19912145#12
		content = content.replace(/\[\[jumpuri:([^\[\]]+) *> *([^\[\]]+)\]\]/g, (match_str, text, url) => {
			return `<a href=${escJsStr(url)}>${htmlEncode(text)}</a>`;
		});

		// Parse '[jump:2]' // 22003928
		content = content.replace(/\[jump:(\d+)\]/g, (match_str, page) => {
			return `<a href=${escJsStr(`#ChapterPage-${page}`)}>Jump to page ${htmlEncode(page)}</a>`;
		});

		// Check undealed markers
		let markers = Array.from(content.matchAll(/\[+[^\[\]]+\]+/g));
		markers = markers.filter(match => {
			// remove dealed images
			const pattern = match.input.substring(match.index-9, match.index + match[0].length+3);
			const isImagePattern = pattern.startsWith('<%= image[') && pattern.endsWith('] %>');

			// remove [newpage]s
			const isNewpagePattern = match[0].includes('[newpage]'); // Why .include: for matches like '[xxx[[newpage]]]blabla]]'
			return !isImagePattern && !isNewpagePattern;
		});
		markers.length && DoLog(LogLevel.Warning, {
			message: 'Undealed markers found',
			chapter: data,
			markers
		});

		// Up to 4 connected newlines (3 empty lines between paragraphs) at once
		content = content.replaceAll(/\n{4,}/g, '\n'.repeat(4));

		// Parse '[newpage]' & Covert into html
		const pageCounter = (start => {
			let num = start;
			return () => start++;
		}) (1);

		content = content.split('[newpage]').map(subContent => {
			// Split content into pages and wrap each page's lines into <p>s
			return subContent.split('\n').map(line => line.trim() ? `<p>${line}</p>` : '<br>').join('\n');
		}).map(pageHTML => {
			const page = pageCounter();
			const page_id = `ChapterPage-${page}`;

			// Remove <br>s at beggining and ending of each page
			pageHTML = pageHTML.replaceAll(/^(<br>|\s)+/g, '').replaceAll(/(<br>|\s)+$/g, '');

			// Add page number to start and end of each page
			const pageNum = `<div class="ChapterBlockMarker">Page ${page}</div>`;
			pageHTML = `${pageNum}\n${pageHTML}\n${pageNum}`;

			// Wrap each page's html in <div id=pageID>
			return `<div id=${escJsStr(page_id)} class="ChapterContentBlock">\n${pageHTML}\n</div>`;
		}).join('\n');

		// Add description to chapter beginning
		let description = data.description;
		description = description
			.replace(/(<br \/>)+/g, '<br>').split('<br>')
			.filter(line => line.trim().length)
			.map(line => `<p>${line}</p>`)
			.join('\n');
		description = `<div id="ChapterDescription" class="ChapterContentBlock">${description}</div>\n`;
		content = description + content;

		// Add cover image to chapter beginning
		const cover = await PixivAPI.safeGet(data.coverUrl, null, 'blob');
		const coverId = `ChapterCover-${data.id}`;
		epub.image(cover, coverId);
		content = `\n<%= image[${escJsStr(coverId)}] %>\n` + content;

		// Add style
		content = '<style>.ChapterContentBlock { border-bottom: solid; padding: 1em 0; } .ChapterBlockMarker { font-size: 1em; text-align: right; }</style>' + content;

		return {
			title: data.title,
			content
		};
	}

	function addLoaded(epub, chapter) {
		epub.add(chapter.title, chapter.content);
	}

	async function addChapter(epub, data) {
		const chapter = await loadChapter(epub, data);
		addLoaded(epub, chapter);
	}

	async function saveEpub(epub, filename, callback=function() {}) {
		const blob = await epub.generate('blob');
		const url = URL.createObjectURL(blob);
		dl_browser(url, filename);
		setTimeout(() => {
			URL.revokeObjectURL(url);
			callback();
		});
	}

	function htmlEncode(text, encodes = '<>\'";&#') {
		return Array.from(text).map(char => !encodes || encodes.includes(char) ? `&#${char.charCodeAt(0)};` : char).join('');
	}

	// Pixiv's js hooked original EventTarget.prototype.addEventListener, using this function to bypass
	function $AEL(elm, ...args) {
		if (!$AEL.addEventListener) {
			const ifr = $$CrE({
				tagName: 'iframe',
				styles: {
					border: 'none',
					padding: 'none',
					width: '0',
					height: '0',
					'z-index': '-9999999',
				},
				props: {
					'srcdoc': '<html></html>'
				}
			});
			document.body.appendChild(ifr);
			$AEL.addEventListener = ifr.contentWindow.EventTarget.prototype.addEventListener;
		}
		return $AEL.addEventListener.apply(elm, args);
	}
})();