整理した

src/server/web/url-preview.ts

@@ -0,0 +1,15 @@
+import * as express from 'express';
+import summaly from 'summaly';
+
+module.exports = async (req: express.Request, res: express.Response) => {
+	const summary = await summaly(req.query.url);
+	summary.icon = wrap(summary.icon);
+	summary.thumbnail = wrap(summary.thumbnail);
+	res.send(summary);
+};
+
+function wrap(url: string): string {
+	return url != null
+		? `https://images.weserv.nl/?url=${url.replace(/^https?:\/\//, '')}`
+		: null;
+}