auto-fanbox-downloader.js

// auto-fanbox-downloader.js
// (c) syuilo 2021
// 注: 私用の際はCORSを無効にしておく必要があります
//     e.g. https://chrome.google.com/webstore/detail/cors-unblock/lfhmikememgdcahcdlaciloancbhjino

// 投稿一覧ページにおける各投稿のクラス
const SELECTOR = '.sc-11axwx2-0.bXrzaX';

const els = document.querySelectorAll(SELECTOR);
	
for (let i = 0; i < els.length; i++) {
	const el = els[i];
	const link = el.children[0];
	const url = link.href;
	const button = document.createElement('button');
	button.innerText = 'download';
	button.addEventListener('click', () => {
		const w = window.open(url, url, 'height=500, width=500');
		w.addEventListener('load', () => {
			downloadPage(w);
		});
		button.innerText = 'downloaded';
	});
	el.appendChild(button);
}

function wait(ms) {
	return new Promise((res, rej) => {
		setTimeout(res, ms)
	});
}

async function downloadPage(w) {
	// 投稿ページにおける各画像のクラス
	const SELECTOR = '.xvj0xk-1.gcZCGE';

	function download(url, fileName) {
		const xhr = new XMLHttpRequest();
		xhr.open('GET', url, true);
		xhr.withCredentials = true;
		xhr.responseType = 'blob';
		xhr.onload = function(e) {
			if (this.status !== 200) {
				alert('Failed to download image :(');
			}

			const imgUrl = URL.createObjectURL(this.response);
			const link = document.createElement('a');
			link.href = imgUrl;
			link.download = fileName;
			document.body.appendChild(link);
			link.click();
			document.body.removeChild(link)
		};
		xhr.send();
	}
	
	// lazyloadを解決するためスクロール
	await wait(1000);
	const height = Math.max(w.document.body.scrollHeight, w.document.body.offsetHeight, w.document.documentElement.clientHeight, w.document.documentElement.scrollHeight, w.document.documentElement.offsetHeight);
	w.scroll({ top: height, behavior: 'smooth' });
	await wait(1000);
	w.scroll({ top: 0, behavior: 'smooth' });
	await wait(1000);

	const els = w.document.querySelectorAll(SELECTOR);
	
	for (let i = 0; i < els.length; i++) {
		const el = els[i];
		const url = el.href;
		const ext = url.split('.').pop();
		const fileName = `${url.split('/')[5]}-${(i + 1).toString().padStart(4, '0')}.${ext}`;
		download(url, fileName);
		await wait(300);
	}
}