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

packages/backend/src/server/api/endpoints.ts

@@ -312,6 +312,7 @@ import * as ep___users_searchByUsernameAndHost from './endpoints/users/search-by
 import * as ep___users_search from './endpoints/users/search.js';
 import * as ep___users_show from './endpoints/users/show.js';
 import * as ep___users_stats from './endpoints/users/stats.js';
+import * as ep___fetchRss from './endpoints/fetch-rss.js';
 
 const eps = [
 	['admin/meta', ep___admin_meta],
@@ -626,6 +627,7 @@ const eps = [
 	['users/search', ep___users_search],
 	['users/show', ep___users_show],
 	['users/stats', ep___users_stats],
+	['fetch-rss', ep___fetchRss],
 ];
 
 export interface IEndpointMeta {

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);
+});