API 路由

了解如何使用 Expo Router 创建服务器端点。

API 路由是一项实验性功能。从 Expo Router v3 开始可用。

Expo Router 使你能够在应用目录中为所有平台编写服务器代码。

¥Expo Router enables you to write server code for all platforms, right in your app directory.

{
  "web": {
    "bundler": "metro",
    "output": "server"
  }
}

服务器功能需要自定义 Node.js 服务器。大多数托管提供商都支持 Node.js，包括 Netlify、Cloudflare 和 Vercel。

¥Server features require a custom Node.js server. Most hosting providers support Node.js, including Netlify, Cloudflare, and Vercel.

什么是 API 路由

¥What are API Routes

API 路由是在路由匹配时执行的函数。它们可用于安全地处理敏感数据，例如 API 密钥，或实现自定义服务器逻辑。API 路由应在符合 WinterCG 的环境中执行。

¥API Routes are functions that are executed when a route is matched. They can be used to handle sensitive data, such as API keys securely, or implement custom server logic. API Routes should be executed in a WinterCG-compliant environment.

API 路由是通过在应用目录中创建扩展名为 +api.ts 的文件来定义的。例如，当路由 /hello 匹配时，执行以下路由处理程序。

¥API Routes are defined by creating files in the app directory with the +api.ts extension. For example, the following route handler is executed when the route /hello is matched.

创建 API 路由

¥Create an API route

export function GET(request: Request) {
  return Response.json({ hello: 'world' });
}

import { Button } from 'react-native';

async function fetchHello() {
  const response = await fetch('/hello');
  const data = await response.json();
  alert('Hello ' + data.hello);
}

export default function App() {
  return <Button onPress={() => fetchHello()} title="Fetch hello" />;
}

{
  "plugins": [
    [
      "expo-router",
      {
        "origin": "https://evanbacon.dev/"
      }
    ]
  ]
}

API 路由文件名不能具有特定于平台的扩展名。例如，hello+api.web.ts 将不起作用。

要求

¥Requests

请求使用全局、标准 Request 对象。

¥Requests use the global, standard Request object.

export async function GET(request: Request, { post }: Record<string, string>) {
  // const postId = request.expoUrl.searchParams.get('post')
  // fetch data for 'post'
  return Response.json({ ... });
}

请求正文

¥Request body

使用 request.json() 函数访问请求正文。它自动解析正文并返回结果。

¥Use the request.json() function to access the request body. It automatically parses the body and returns the result.

export async function POST(request: Request) {
  const body = await request.json();

  return Response.json({ ... });
}

响应

¥Response

响应使用全局标准 Response 对象。

¥Responses use the global, standard Response object.

export function GET() {
  return Response.json({ hello: 'universe' });
}

错误

¥Errors

你可以使用 Response 对象来响应服务器错误。

¥You can respond to server errors by using the Response object.

import { Request, Response } from 'expo-router/server';

export async function GET(request: Request, { post }: Record<string, string>) {
  if (!post) {
    return new Response('No post found', {
      status: 404,
      headers: {
        'Content-Type': 'text/plain',
      },
    });
  }
  // fetch data for `post`
  return Response.json({ ... });
}

使用未定义的方法发出请求将自动返回 405: Method not allowed。如果请求过程中抛出错误，会自动返回 500: Internal server error。

¥Making requests with an undefined method will automatically return 405: Method not allowed. If an error is thrown during the request, it will automatically return 500: Internal server error.

打包

¥Bundling

API 路由与 Expo CLI 和 Metro 打包器 打包在一起。他们可以访问所有语言功能作为你的客户端代码：

¥API Routes are bundled with Expo CLI and Metro bundler. They have access to all of the language features as your client code:

• TypeScript — 类型和 tsconfig.json 路径。

  ¥TypeScript — types and tsconfig.json paths.

• 环境变量 — 服务器路由可以访问所有环境变量，而不仅仅是前缀为 EXPO_PUBLIC_ 的变量。

  ¥Environment variables — server routes have access to all environment variables, not just the ones prefixed with EXPO_PUBLIC_.

• Node.js 标准库 — 确保你在本地为你的服务器环境使用正确版本的 Node.js。

  ¥Node.js standard library — ensure that you are using the correct version of Node.js locally for your server environment.

• babel.config.js 和 Metro.config.js 支持 — 设置可跨客户端和服务器代码工作。

  ¥babel.config.js and metro.config.js support — settings work across both client and server code.

安全

¥Security

路由处理程序在与客户端代码隔离的沙盒环境中执行。这意味着你可以安全地将敏感数据存储在路由处理程序中，而无需将其暴露给客户端。

¥Route handlers are executed in a sandboxed environment that is isolated from the client code. It means you can safely store sensitive data in the route handlers without exposing it to the client.

• 导入带有密钥的代码的客户端代码包含在客户端打包包中。它适用于应用目录中的所有文件，即使它们不是路由处理程序文件（例如以 +api.ts 为后缀的文件）。

  ¥Client code that imports code with a secret is included in the client bundle. It applies to all files in the app directory even though they are not a route handler file (such as suffixed with +api.ts).

• 如果密钥位于 <...>+api.ts 文件中，则它不包含在客户端包中。它适用于在路由处理程序中导入的所有文件。

  ¥If the secret is in a <...>+api.ts file, it is not included in the client bundle. It applies to all files that are imported in the route handler.

• 秘密剥离发生在 expo/metro-config 中，并要求在 Metro.config.js 中使用。

  ¥The secret stripping takes place in expo/metro-config and requires it to be used in the metro.config.js.

部署

¥Deployment

这是实验性的，可能会发生重大变化。我们没有针对此配置进行持续测试。

每个云托管提供商都需要一个自定义适配器来支持 Expo 服务器运行时。以下第三方提供商获得了 Expo 团队的非官方或实验性支持。

¥Every cloud hosting provider needs a custom adapter to support the Expo server runtime. The following third-party providers have unofficial or experimental support from the Expo team.

在部署到这些提供商之前，最好熟悉 npx expo export 命令的基础知识：

¥Before deploying to these providers, it may be good to be familiar with the basics of npx expo export command:

• /dist 是 Expo CLI 的默认导出目录。

  ¥**/dist** is the default export directory for Expo CLI.

• /public 中的文件在导出时复制到 /dist。

  ¥Files in /public are copied to /dist on export.

• @expo/server 包包含在 expo 中，并将请求委托给服务器路由。

  ¥The @expo/server package is included with expo and delegates requests to the server routes.

• @expo/server 不会从 .env 文件中增加环境变量。它们预计由托管提供商或用户加载。

  ¥@expo/server does not inflate environment variables from .env files. They are expected to load either by the hosting provider or the user.

• Metro 不包含在服务器中。

  ¥Metro is not included in the server.

表达

¥Express

#!/usr/bin/env node

const path = require('path');
const { createRequestHandler } = require('@expo/server/adapter/express');

const express = require('express');
const compression = require('compression');
const morgan = require('morgan');

const CLIENT_BUILD_DIR = path.join(process.cwd(), 'dist/client');
const SERVER_BUILD_DIR = path.join(process.cwd(), 'dist/server');

const app = express();

app.use(compression());

// http://express.nodejs.cn/en/advanced/best-practice-security.html#at-a-minimum-disable-x-powered-by-header
app.disable('x-powered-by');

process.env.NODE_ENV = 'production';

app.use(
  express.static(CLIENT_BUILD_DIR, {
    maxAge: '1h',
    extensions: ['html'],
  })
);

app.use(morgan('tiny'));

app.all(
  '*',
  createRequestHandler({
    build: SERVER_BUILD_DIR,
  })
);
const port = process.env.PORT || 3000;

app.listen(port, () => {
  console.log(`Express server listening on port ${port}`);
});

Netlify

这是实验性的，可能会发生重大变化。我们没有针对此配置进行持续测试。

const { createRequestHandler } = require('@expo/server/adapter/netlify');

const handler = createRequestHandler({
  build: require('path').join(__dirname, '../../dist/server'),
});

module.exports = { handler };

[build]
  command = "expo export -p web"
  functions = "netlify/functions"
  publish = "dist/client"

[[redirects]]
  from = "/*"
  to = "/.netlify/functions/server"
  status = 404

[functions]
  # Include everything to ensure dynamic routes can be used.
  included_files = ["dist/server/**/*"]

[[headers]]
  for = "/dist/server/_expo/functions/*"
  [headers.values]
    # Set to 60 seconds as an example.
    "Cache-Control" = "public, max-age=60, s-maxage=60"

Vercel

这是实验性的，可能会发生重大变化。我们没有针对此配置进行持续测试。

const { createRequestHandler } = require('@expo/server/adapter/vercel');

module.exports = createRequestHandler({
  build: require('path').join(__dirname, '../dist/server'),
});

{
  "version": 2,
  "outputDirectory": "dist",
  "builds": [
    {
      "src": "package.json",
      "use": "@vercel/static-build",
      "config": {
        "distDir": "dist/client"
      }
    },
    {
      "src": "api/index.ts",
      "use": "@vercel/node",
      "config": {
        "includeFiles": ["dist/server/**"]
      }
    }
  ],
  "routes": [
    {
      "handle": "filesystem"
    },
    {
      "src": "/(.*)",
      "dest": "/api/index.ts"
    }
  ]
}

{
  "buildCommand": "expo export -p web",
  "outputDirectory": "dist/client",
  "functions": {
    "api/index.ts": {
      "runtime": "@vercel/node@3.0.11",
      "includeFiles": "dist/server/**"
    }
  },
  "rewrites": [
    {
      "source": "/(.*)",
      "destination": "/api/index.ts"
    }
  ]
}

已知的限制

¥Known limitations

API Routes beta 版本当前不支持多个已知功能。

¥Several known features are not currently supported in the API Routes beta release.

无动态导入

¥No dynamic imports

API 路由目前的工作方式是将所有代码（不包括 Node.js 内置代码）打包到一个文件中。这意味着你不能使用任何未与服务器打包的外部依赖。例如，无法使用诸如 sharp 之类的包含多个平台二进制文件的库。这将在未来版本中解决。

¥API Routes currently work by bundling all code (minus the Node.js built-ins) into a single file. This means that you cannot use any external dependencies that are not bundled with the server. For example, a library such as sharp, which includes multiple platform binaries, cannot be used. This will be addressed in a future version.

不支持 ESM

¥ESM not supported

当前的打包实现选择更加统一而不是灵活。这意味着原生不支持 ESM 的限制将转移到 API 路由中。所有代码都将被转译为 Common JS (require/module.exports)。但是，无论如何，我们建议你使用 ESM 编写 API 路由。这将在未来版本中解决。

¥The current bundling implementation opts to be more unified than flexible. This means the limitation of native not supporting ESM is carried over to API Routes. All code will be transpiled down to Common JS (require/module.exports). However, we recommend you write API Routes using ESM regardless. This will be addressed in a future version.