feat(route): add Discourse official rss route (#16681)

* add discourse official rss rule

* fix issues with existing interfaces

* optimize path parameters and add annotation

---------

lib/routes/discourse/official.ts

@@ -0,0 +1,55 @@
+import { Route } from '@/types';
+import { getConfig } from './utils';
+import got from '@/utils/got';
+import RSSParser from '@/utils/rss-parser';
+
+export const route: Route = {
+    path: '/:configId/official/:path{.+}',
+    categories: ['bbs'],
+    example: '/discourse/0/official/latest',
+    parameters: {
+        configId: 'Environment variable configuration id, see above',
+        path: 'Discourse RSS path between `domain` and `.rss`. All supported Rss path can be found in [https://meta.discourse.org/t/finding-discourse-rss-feeds/264134](https://meta.discourse.org/t/finding-discourse-rss-feeds/264134). For example: the path of [https://meta.discourse.org/top/all.rss](https://meta.discourse.org/top/all.rss) is `top/all`.',
+    },
+    features: {
+        requireConfig: [
+            {
+                name: 'DISCOURSE_CONFIG_*',
+                description: `Configure the Discourse environment variables referring to [https://docs.rsshub.app/deploy/config#discourse](https://docs.rsshub.app/deploy/config#discourse).`,
+            },
+        ],
+        requirePuppeteer: false,
+        antiCrawler: false,
+        supportBT: false,
+        supportPodcast: false,
+        supportScihub: false,
+    },
+    name: 'Official RSS',
+    maintainers: ['Raikyou', 'dzx-dzx'],
+    handler,
+};
+
+async function handler(ctx) {
+    const { link, key } = getConfig(ctx);
+    const path = ctx.req.param('path');
+
+    const url = `${link}/${path}.rss`;
+
+    const feed = await RSSParser.parseString(
+        (
+            await got(url, {
+                headers: {
+                    'User-Api-Key': key,
+                },
+            })
+        ).data
+    );
+
+    feed.items = feed.items.map((e) => ({
+        description: e.content,
+        author: e.creator,
+        ...e,
+    }));
+
+    return { item: feed.items, ...feed };
+}