docs: add zh-hans on middleware page

apps/docs-app/docs/introduction.md

@@ -15,7 +15,7 @@ Similar to other meta-frameworks such as Next.JS, Nuxt, SvelteKit, Qwik City, an
 - Supports Vite/Vitest/Playwright
 - Server and deployment integrations powered by [Nitro](https://nitro.unjs.io)
 - [File-based routing](/docs/features/routing/overview)
-- [Server-side data fetching](/docs/features/data-fetching/server-side-data-fetching.md)
+- [Server-side data fetching](/docs/features/data-fetching/server-side-data-fetching)
 - [Support for using Markdown as content routes](/docs/features/routing/content)
 - [API/server routes](/docs/features/api/overview)
 - Hybrid [SSR](/docs/features/server/server-side-rendering)/[SSG support](/docs/features/server/static-site-generation)

apps/docs-app/i18n/zh-hans/docusaurus-plugin-content-docs/current.json

@@ -84,6 +84,10 @@
     "message": "内容路由",
     "description": "The label for the doc item Content Routes in sidebar docsSidebar, linking to the doc features/routing/content"
   },
+  "sidebar.docsSidebar.doc.Middleware": {
+    "message": "中间件",
+    "description": "The label for the doc item Middleware in sidebar docsSidebar, linking to the doc features/routing/middleware"
+  },
   "sidebar.docsSidebar.doc.Providers": {
     "message": "服务器提供商",
     "description": "The label for the doc item Providers in sidebar docsSidebar, linking to the doc features/deployment/providers"

apps/docs-app/i18n/zh-hans/docusaurus-plugin-content-docs/current/features/routing/content.md

@@ -288,7 +288,7 @@ export default class BlogPostComponent {
 }
 ```
 
-### 使用源标签解析器
+### 使用 meta 标签解析器
 
 在路由配置中通过为 `RouteMeta` 对象的 `meta` 属性设置一个 `postMetaResolver` 函数，可以为一个路由解析 meta 标签。
 

apps/docs-app/i18n/zh-hans/docusaurus-plugin-content-docs/current/features/routing/middleware.md

@@ -0,0 +1,52 @@
+# 中间件
+
+Analog 支持服务端中间件，可以用于修改请求，检查认证，发送跳转等其他操作。
+
+## 设置中间件
+
+位于 `src/server/middleware` 目录下的中间件会自动被注册。
+
+```treeview
+src/
+└── server/
+    └── middleware/
+        └── auth.ts
+```
+
+中间件通过 `defineEventHandler` 函数来定义。
+
+```ts
+import { defineEventHandler, sendRedirect, setHeaders } from 'h3';
+
+export default eventHandler((event) => {
+  if (event.node.req.originalUrl === '/checkout') {
+    console.log('event url', event.node.req.originalUrl);
+
+    setHeaders(event, {
+      'x-analog-checkout': 'true',
+    });
+  }
+});
+```
+
+- 中间件应该只修改请求并且没有任何返回值！
+- 中间件按照文件名的顺序执行。如果要自定义顺序，建议给文件名上加上数字前缀来实现。
+
+## 中间件的筛选器
+
+中间件可以通过筛选器只处理特定的路由。
+
+```ts
+export default defineEventHandler(async (event) => {
+  // Only execute for /admin routes
+  if (getRequestURL(event).pathname.startsWith('/admin')) {
+    const cookies = parseCookies(event);
+    const isLoggedIn = cookies['authToken'];
+
+    // check auth and redirect
+    if (!isLoggedIn) {
+      sendRedirect(event, '/login', 401);
+    }
+  }
+});
+```