Cloudflare Workers 实战完全指南 2026：零成本反代 + Pages 部署 + R2 对象存储

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export default {
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  async fetch(request, env) {
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    // API Key 从 wrangler secret 读取，不出现在代码中
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    const headers = new Headers(request.headers);
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    headers.set("Authorization", `Bearer ${env.OPENAI_API_KEY}`);
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    const url = new URL(request.url);
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    url.hostname = "api.openai.com";
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    // 只允许特定路径
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    const allowedPaths = ["/v1/chat/completions", "/v1/models"];
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    if (!allowedPaths.some(p => url.pathname.startsWith(p))) {
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      return new Response("Not Found", { status: 404 });
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    }
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    return fetch(new Request(url.toString(), {
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      method:  request.method,
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      headers: headers,
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      body:    request.body,
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    }));
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  },
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};

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export default {
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  async fetch(request) {
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    const CORS_HEADERS = {
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      "Access-Control-Allow-Origin":  "*",
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      "Access-Control-Allow-Methods": "GET, POST, PUT, DELETE, OPTIONS",
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      "Access-Control-Allow-Headers": "Content-Type, Authorization",
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    };
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    // 处理 OPTIONS 预检请求
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    if (request.method === "OPTIONS") {
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      return new Response(null, { status: 204, headers: CORS_HEADERS });
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    }
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    const url = new URL(request.url);
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    url.hostname = "api.example.com";
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    const response = await fetch(new Request(url.toString(), request));
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    const newHeaders = new Headers(response.headers);
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    for (const [k, v] of Object.entries(CORS_HEADERS)) newHeaders.set(k, v);
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    return new Response(response.body, { status: response.status, headers: newHeaders });
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  },
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};

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my-site/
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├── public/          # 静态文件
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├── src/             # Astro 页面
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└── functions/       # 自动部署为 Workers
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    ├── api/
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    │   └── hello.ts    # GET /api/hello
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    └── _middleware.ts  # 全局中间件

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// wrangler.toml:
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// [[r2_buckets]]
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// binding = "MY_BUCKET"
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// bucket_name = "my-bucket"
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export default {
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  async fetch(request, env) {
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    const key = new URL(request.url).pathname.slice(1);
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    switch (request.method) {
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      case "GET": {
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        const obj = await env.MY_BUCKET.get(key);
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        if (!obj) return new Response("Not Found", { status: 404 });
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        const headers = new Headers();
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        obj.writeHttpMetadata(headers);
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        headers.set("etag", obj.httpEtag);
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        headers.set("Cache-Control", "public, max-age=31536000");
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        return new Response(obj.body, { headers });
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      }
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      case "PUT": {
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        const ct = request.headers.get("Content-Type") ?? "application/octet-stream";
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        await env.MY_BUCKET.put(key, request.body, {
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          httpMetadata: { contentType: ct },
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        });
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        return new Response(`OK: ${key}`, { status: 201 });
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      }
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      case "DELETE": {
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        await env.MY_BUCKET.delete(key);
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        return new Response("Deleted");
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      }
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      default:
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        return new Response("Method Not Allowed", { status: 405 });
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    }
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  },
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};

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import { S3Client, PutObjectCommand, GetObjectCommand } from "@aws-sdk/client-s3";
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// 只需替换 endpoint，其余与 S3 完全一样
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const r2 = new S3Client({
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  region: "auto",
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  endpoint: `https://${process.env.CF_ACCOUNT_ID}.r2.cloudflarestorage.com`,
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  credentials: {
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    accessKeyId:     process.env.R2_ACCESS_KEY_ID!,
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    secretAccessKey: process.env.R2_SECRET_ACCESS_KEY!,
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  },
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});
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// 上传
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await r2.send(new PutObjectCommand({
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  Bucket:      "my-bucket",
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  Key:         "images/avatar.png",
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  Body:        fileBuffer,
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  ContentType: "image/png",
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}));