PreviewLinks

Preview links and show their titles with caching for 3 days

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(I already have a user script manager, let me install it!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name         PreviewLinks
// @namespace    https://jirehlov.com
// @version      0.2.8
// @description  Preview links and show their titles with caching for 3 days
// @author       Jirehlov
// @include      /^https?://(bangumi\.tv|bgm\.tv|chii\.in)/.*
// @grant        none
// @license      MIT
// ==/UserScript==

(function () {
	"use strict";
	const CACHE_PREFIX = "PLinksCache_";
	const CACHE_EXPIRATION = 7 * 24 * 60 * 60 * 1000;
	const getTitleFromLink = async link => {
		const linkURL = link.href;
		const cachedTitle = getCachedTitle(linkURL);
		if (cachedTitle !== null) {
			return cachedTitle;
		}
		try {
			let title = "";
			if (link.textContent === link.href) {
				const response = await fetch(linkURL);
				const data = await response.text();
				const parser = new DOMParser();
				const htmlDoc = parser.parseFromString(data, "text/html");
				const titleElement = htmlDoc.querySelector("h1.nameSingle a");
				const blogTitleElement = htmlDoc.querySelector("h1");
				const epTitleElement = htmlDoc.querySelector("h2.title");
				title = titleElement ? titleElement.textContent : "";
				const chineseName = titleElement ? titleElement.getAttribute("title") : "";
				if (chineseName && (link.href.includes("subject") || link.href.includes("ep"))) {
					title += title ? ` | ${ chineseName }` : chineseName;
				}
				if (link.href.includes("ep") && epTitleElement) {
					epTitleElement.querySelectorAll("small").forEach(small => small.remove());
					const epTitle = epTitleElement.textContent.trim();
					title += title ? ` | ${ epTitle }` : epTitle;
				}
				if ((link.href.includes("blog") || link.href.includes("topic") || link.href.includes("index")) && blogTitleElement) {
					title = blogTitleElement.textContent.trim();
				}
				const prefix = link.href.match(/\/(subject\/topic|subject|ep|character|person|blog|group\/topic|index)\/[^/]+/);
				const prefixText = prefix ? `[${ prefix[1] }] ` : "";
				title = prefixText + title;
				cacheTitle(linkURL, title);
				return title;
			} else {
				return null;
			}
		} catch (error) {
			console.error("Error fetching data:", error);
			return null;
		}
	};
	const cacheTitle = (url, title) => {
		const cacheKey = CACHE_PREFIX + url;
		const cacheValue = {
			title: title,
			timestamp: Date.now()
		};
		localStorage.setItem(cacheKey, JSON.stringify(cacheValue));
	};
	const getCachedTitle = url => {
		const cacheKey = CACHE_PREFIX + url;
		const cacheValue = localStorage.getItem(cacheKey);
		if (cacheValue !== null) {
			const {title, timestamp} = JSON.parse(cacheValue);
			if (Date.now() - timestamp < CACHE_EXPIRATION) {
				return title;
			} else {
				localStorage.removeItem(cacheKey);
			}
		}
		return null;
	};
	const domains = [
		"bgm.tv",
		"chii.in",
		"bangumi.tv"
	];
	const paths = [
		"subject/",
		"ep/",
		"character/",
		"person/",
		"blog/",
		"group/topic/",
		"index/"
	];
	const selectors = [];
	domains.forEach(domain => {
		paths.forEach(path => {
			selectors.push(`a[href^="https://${ domain }/${ path }"]`);
		});
	});
	const allLinks = document.querySelectorAll(selectors.join(","));
	const fetchAndReplaceLinkText = () => {
		let index = 0;
		const processNextLink = async () => {
			if (index < allLinks.length) {
				const link = allLinks[index];
				const cachedTitle = getCachedTitle(link.href);
				if (link.textContent === link.href) {
					if (cachedTitle) {
						link.textContent = cachedTitle;
					} else {
						const title = await getTitleFromLink(link);
						if (title) {
							link.textContent = title;
						}
						setTimeout(processNextLink, 3000);
						return;
					}
				}
				index++;
				processNextLink();
			}
		};
		processNextLink();
	};
	fetchAndReplaceLinkText();
}());