feat(server): add fetch-rss api to reduce dependency of external apis

packages/backend/src/server/api/endpoints/fetch-rss.ts

@@ -0,0 +1,39 @@
+import Parser from 'rss-parser';
+import { getResponse } from '@/misc/fetch.js';
+import config from '@/config/index.js';
+import define from '../define.js';
+
+const rssParser = new Parser();
+
+export const meta = {
+	tags: ['meta'],
+
+	requireCredential: false,
+	allowGet: true,
+	cacheSec: 60 * 3,
+} as const;
+
+export const paramDef = {
+	type: 'object',
+	properties: {
+		url: { type: 'string' },
+	},
+	required: ['url'],
+} as const;
+
+// eslint-disable-next-line import/no-default-export
+export default define(meta, paramDef, async (ps) => {
+	const res = await getResponse({
+		url: ps.url,
+		method: 'GET',
+		headers: Object.assign({
+			'User-Agent': config.userAgent,
+			Accept: 'application/rss+xml, */*',
+		}),
+		timeout: 5000,
+	});
+
+	const text = await res.text();
+
+	return rssParser.parseString(text);
+});