Improve URL preview (#2465)

* Twitter, YouTube

* Twitch

src/server/web/url-preview.ts

@@ -1,5 +1,5 @@
 import * as Koa from 'koa';
-import summaly from 'summaly';
+import { Summary } from 'summaly';
 import { fetchMeta } from '../../misc/fetch-meta';
 import Logger from '../../services/logger';
 import config from '../../config';
@@ -9,20 +9,44 @@ import { sanitizeUrl } from '../../misc/sanitize-url';
 
 const logger = new Logger('url-preview');
 
+//#region SummaryInstance
+let summaryInstance: Summary | null = null;
+
+function getSummaryInstance(): Summary {
+	if (summaryInstance) return summaryInstance;
+	summaryInstance = new Summary({
+		allowedPlugins: [
+			'twitter',
+			'youtube',
+		],
+	});
+	return summaryInstance;
+}
+//#endregion
+
+
 module.exports = async (ctx: Koa.Context) => {
 	const meta = await fetchMeta();
 
+	const url = sanitizeUrl(ctx.query.url);
+	if (url == null) {
+		ctx.status = 400;
+		ctx.set('Cache-Control', 'max-age=3600');
+		return;
+	}
+
+	const lang = ctx.query.lang || 'ja-JP';
+
 	logger.info(meta.summalyProxy
-		? `(Proxy) Getting preview of ${ctx.query.url}@${ctx.query.lang} ...`
-		: `Getting preview of ${ctx.query.url}@${ctx.query.lang} ...`);
+		? `(Proxy) Getting preview of ${url}@${lang} ...`
+		: `Getting preview of ${url}@${lang} ...`);
 
 	try {
 		const summary = meta.summalyProxy ? await getJson(`${meta.summalyProxy}?${query({
-			url: ctx.query.url,
-			lang: ctx.query.lang || 'ja-JP'
-		})}`) : await summaly(ctx.query.url, {
-			followRedirects: false,
-			lang: ctx.query.lang || 'ja-JP'
+			url: url,
+			lang: lang
+		})}`) : await getSummaryInstance().summary(url, {
+			lang: lang
 		});
 
 		logger.succ(`Got preview of ${ctx.query.url}: ${summary.title}`);
@@ -33,14 +57,18 @@ module.exports = async (ctx: Koa.Context) => {
 		if (summary.player) summary.player.url = sanitizeUrl(summary.player.url);
 		summary.url = sanitizeUrl(summary.url);
 
+		if (summary.player?.url?.startsWith('https://player.twitch.tv/')) {
+			summary.player.url = summary.player.url.replace('parent=meta.tag', `parent=${config.url.replace(/^https?:[/][/]/, '')}`);
+		}
+
 		// Cache 7days
 		ctx.set('Cache-Control', 'max-age=604800, immutable');
 
 		ctx.body = summary;
 	} catch (e) {
 		logger.warn(`Failed to get preview of ${ctx.query.url}: ${e}`);
 		ctx.status = 200;
-		ctx.set('Cache-Control', 'max-age=86400, immutable');
+		ctx.set('Cache-Control', 'max-age=3600, immutable');
 		ctx.body = '{}';
 	}
 };