feat(route/substack): add substack subscription by official rss

lib/routes/substack/namespace.ts

@@ -0,0 +1,7 @@
+import type { Namespace } from '@/types';
+
+export const namespace: Namespace = {
+    name: 'Substack',
+    url: 'substack.com',
+    lang: 'en',
+};

lib/routes/substack/subscribe.ts

@@ -0,0 +1,48 @@
+import { Route, ViewType } from '@/types';
+import parser from '@/utils/rss-parser';
+import { parseDate } from '@/utils/parse-date';
+import InvalidParameterError from '@/errors/types/invalid-parameter';
+
+export const route: Route = {
+    path: '/subscribe/:user',
+    categories: ['blog'],
+    view: ViewType.SocialMedia,
+    example: '/substack/subscribe/mangoread',
+    parameters: { user: 'Username of the Substack' },
+    features: {
+        requireConfig: false,
+        requirePuppeteer: false,
+        antiCrawler: false,
+        supportBT: false,
+        supportPodcast: false,
+        supportScihub: false,
+    },
+    name: 'Substack Subscription',
+    maintainers: ['pseudoyu'],
+    handler,
+};
+
+async function handler(ctx) {
+    const user = ctx.req.param('user');
+
+    if (!user) {
+        throw new InvalidParameterError('Invalid user');
+    }
+
+    const feed = await parser.parseURL(`https://${user}.substack.com/feed`);
+
+    return {
+        title: feed.title ?? 'Substack',
+        description: feed.description ?? `${user}'s Substack`,
+        link: feed.link ?? `https://${user}.substack.com`,
+        image: feed.image?.url ?? '',
+        item: feed.items.map((item) => ({
+            title: item.title ?? 'Untitled',
+            description: item['content:encoded'] ?? item.content ?? '',
+            link: item.link ?? '',
+            pubDate: item.pubDate ? parseDate(item.pubDate) : undefined,
+            guid: item.guid ?? '',
+            author: item.creator ?? user,
+        })),
+    };
+}