feat: add rss building utils but yet to applied to production stage

docs/.vitepress/theme/rss.ts

@@ -0,0 +1,77 @@
+import { dirname } from 'path'
+import fg from 'fast-glob'
+import fs from 'fs-extra'
+import matter from 'gray-matter'
+import MarkdownIt from 'markdown-it'
+import type { FeedOptions, Item } from 'feed'
+import { Feed } from 'feed'
+
+const DOMAIN = 'https://note.toshiki.dev'
+const AUTHOR = {
+    name: 'Anda Toshiki',
+    email: 'hello@toshiki.dev',
+    link: DOMAIN,
+}
+const OPTIONS: FeedOptions = {
+    title: "Toshiki's Notebook",
+    description: "Toshiki's web notebook built upon Vitepress and deployed via Vercel!",
+    id: `${DOMAIN}/`,
+    link: `${DOMAIN}/`,
+    copyright: 'MIT License',
+    feedLinks: {
+        json: DOMAIN + '/feed.json',
+        atom: DOMAIN + '/feed.atom',
+        rss: DOMAIN + '/feed.xml',
+    },
+    author: AUTHOR,
+    image: 'https://note.toshiki.dev/logos/logo-308px.svg',
+    favicon: 'https://note.toshiki.dev/logos/logo-308px.svg',
+}
+
+const markdown = MarkdownIt({
+    html: true,
+    breaks: true,
+    linkify: true,
+})
+
+export async function buildDocsRSS() {
+    const posts = await generateRSS()
+    writeFeed('feed', posts)
+}
+
+async function generateRSS() {
+    const files = await fg('docs/*.md')
+
+    const posts: any[] = (
+        await Promise.all(
+            files
+                .filter(i => !i.includes('index'))
+                .map(async i => {
+                    const raw = await fs.readFile(i, 'utf-8')
+                    const { data, content } = matter(raw)
+                    const html = markdown.render(content).replace('src="/', `src="${DOMAIN}/`)
+
+                    return {
+                        ...data,
+                        date: new Date(data.date),
+                        content: html,
+                        author: [AUTHOR],
+                        link: `${DOMAIN}/${i.replace('.md', '.html')}`,
+                    }
+                })
+        )
+    ).filter(Boolean)
+
+    posts.sort((a, b) => +new Date(b.date) - +new Date(a.date))
+    return posts
+}
+
+async function writeFeed(name: string, items: Item[]) {
+    const feed = new Feed(OPTIONS)
+    items.forEach(item => feed.addItem(item))
+
+    await fs.ensureDir(dirname(`./dist/${name}`))
+    await fs.writeFile(`./dist/${name}.xml`, feed.rss2(), 'utf-8')
+    await fs.writeFile(`./dist/${name}.atom`, feed.atom1(), 'utf-8')
+    await fs.writeFile(`./dist/${name}.json`, feed.json1(), 'utf-8')
+}