Edge Computing with Cloudflare Workers & Deno · 강의

Deno를 활용한 데이터베이스 프록시

Deno와 Workers를 사용하여 기존 데이터베이스 또는 서버리스 데이터베이스에 연결하는 효율적인 데이터베이스 프록시를 만듭니다.

Deno를 활용한 데이터베이스 프록시은(는) CoddyKit의 무료 Edge Computing with Cloudflare Workers & Deno 강의입니다. 이것은 4개 중 3번째 강의입니다. 아래에서 전체 강의를 무료로 읽을 수 있으며, 내장 코드 에디터와 24/7 AI 튜터와 함께 브라우저에서 직접 실습할 수 있습니다. 이 강의는 Edge Computing with Cloudflare Workers & Deno 학습 경로의 일부이며, 진행 상황이 웹과 CoddyKit 앱에 동기화됩니다. Edge Computing with Cloudflare Workers & Deno 강의에는 총 4개의 강의가 포함되어 있습니다.

이 강의의 일부는 아직 번역되지 않았으며 영어로 표시됩니다.

What are Database Proxies?

Welcome to our lesson on Deno database proxies! An edge database proxy acts as an intermediary layer between your application (like a Cloudflare Worker) and your database.

Instead of your edge function connecting directly to the database, it talks to the proxy. The proxy then handles the actual database connection.

Why use them? They centralize connection management, enhance security, and enable data transformation before reaching your database.

Why Deno for Proxies?

Deno is an excellent choice for building these database proxies at the edge. Here's why:

Native HTTP Server: Deno has a powerful, built-in web server, perfect for handling proxy requests.
Security Model: Its granular permission system means you explicitly grant network or file access, enhancing security.
Performance: Deno's fast startup times and efficient runtime make it suitable for responsive proxy services.
TypeScript First: Built-in TypeScript support helps you write more robust and maintainable code for your proxy logic.

Your First Deno Proxy Server

Let's start by creating a basic Deno HTTP server. This server will listen for incoming requests and respond with a simple message, acting as the foundation for our proxy.

Try running this example:

Deno.serve(async (req) => {
  const url = new URL(req.url);
  if (url.pathname === "/") {
    return new Response("Deno Proxy is running!", { status: 200 });
  }
  return new Response("Not Found", { status: 404 });
}, { port: 8000 });

console.log("Deno proxy listening on http://localhost:8000");

Forwarding Requests to DB

Now, let's modify our Deno proxy to forward incoming requests to a 'mock' database endpoint. In a real scenario, this would be your actual database API or a service that interacts with it.

Here, we use a public JSONPlaceholder API to simulate a database call.

Deno.serve(async (req) => {
  // Mock database endpoint (e.g., a public API)
  const mockDbApi = "https://jsonplaceholder.typicode.com/posts";
  const url = new URL(req.url);

  // Construct the target URL for the actual database call
  let targetUrl = mockDbApi;
  if (url.pathname !== "/") {
    targetUrl += url.pathname; // Append path for specific resources
  }

  const proxyReq = new Request(targetUrl, {
    method: req.method,
    headers: req.headers, // Pass original headers
    body: req.body,       // Pass original body
  });

  try {
    const dbResponse = await fetch(proxyReq);
    // Add a custom header to indicate proxy processing
    const newResponse = new Response(dbResponse.body, dbResponse);
    newResponse.headers.set("X-Proxy-By", "Deno");
    return newResponse;
  } catch (error) {
    return new Response(`Proxy Error: ${error.message}`, { status: 500 });
  }
}, { port: 8000 });

console.log("Deno proxy forwarding on http://localhost:8000");

The Need for Connection Pooling

Database connections are expensive to establish. Serverless functions, like Cloudflare Workers, are often short-lived and stateless. If each Worker instance opens a new connection, you can quickly exhaust database connection limits.

Connection pooling is a technique where a pool of open, reusable database connections is maintained. When a request comes in, a connection is borrowed from the pool instead of creating a new one.

Proxy's Role in Pooling

A Deno database proxy can effectively manage connection pooling. Unlike ephemeral Workers, a Deno proxy (e.g., deployed on Deno Deploy or a persistent server) can be a long-lived process.

This allows it to maintain and manage a pool of database connections, serving multiple requests from various Workers without constantly opening and closing connections. This significantly reduces overhead and improves database performance and stability.

Secure Your Database Proxy

Security is paramount. Your Deno proxy acts as a gateway to your database, so it must be secured:

Hide Credentials: Never expose raw database credentials in your Worker code. The proxy should store and use these securely.
Authentication for Proxy: Implement authentication (e.g., API keys, JWTs) for your Workers to access the proxy itself. This ensures only authorized edge functions can send requests.
Permissions: Deno's explicit permission model helps. Only grant the proxy network access to your database, not arbitrary internet access.

Transforming Data at the Edge

Beyond just forwarding, a Deno proxy can transform data. This means modifying request bodies before sending them to the database or altering responses before returning them to the Worker.

This is useful for adding metadata, filtering sensitive information, or normalizing data formats.

Deno.serve(async (req) => {
  const mockDbApi = "https://jsonplaceholder.typicode.com/posts";
  const url = new URL(req.url);
  let targetUrl = mockDbApi;

  // Only transform POST requests for simplicity
  if (req.method === "POST") {
    let requestBody = await req.json(); // Assuming JSON body
    requestBody.processedAt = new Date().toISOString(); // Add a timestamp
    requestBody.source = "edge-proxy"; // Add a source identifier

    const proxyReq = new Request(targetUrl, {
      method: req.method,
      headers: {
        ...req.headers,
        "Content-Type": "application/json" // Ensure correct type
      },
      body: JSON.stringify(requestBody), // Send modified body
    });
    const dbResponse = await fetch(proxyReq);
    return new Response(dbResponse.body, dbResponse);
  } else {
    // For other methods, just forward
    const dbResponse = await fetch(new Request(targetUrl, req));
    return new Response(dbResponse.body, dbResponse);
  }
}, { port: 8000 });

console.log("Deno proxy with data transformation on http://localhost:8000");

Worker to Deno Proxy Flow

How would a Cloudflare Worker interact with this Deno proxy?

The Worker would simply make a standard HTTP fetch request to the Deno proxy's endpoint. If your Deno proxy is deployed on a platform like Deno Deploy, it will have a public URL.

The Worker sends its request, the Deno proxy processes it (e.g., handles pooling, adds security, transforms data), and then forwards it to the actual database, returning the database's response to the Worker.

Deno Proxy Benefits?

Which of the following are benefits of using a Deno-based database proxy at the edge?

Lesson Summary

In this lesson, we explored how to create efficient database proxies using Deno. We learned that Deno's native HTTP server and security model make it ideal for this task.

We built a basic proxy that forwards requests.
Understood the importance of connection pooling and the proxy's role in it.
Discussed securing your proxy and transforming data at the edge.
Finally, we saw how Cloudflare Workers can interact with such a proxy.

This pattern provides a powerful way to manage database interactions from your edge applications.

자주 묻는 질문

“Deno를 활용한 데이터베이스 프록시” 강의는 무료인가요?

네 — “Deno를 활용한 데이터베이스 프록시” 전체 내용을 이 웹사이트에서 무료로 읽을 수 있습니다. 인터랙티브하게 실습하려면(내장 코드 에디터와 24/7 AI 튜터), CoddyKit PRO로 업그레이드하면 Edge Computing with Cloudflare Workers & Deno 강의 전체를 잠금 해제할 수 있습니다. Edge Computing with Cloudflare Workers & Deno 강의에는 총 4개의 강의가 포함되어 있습니다.

“Deno를 활용한 데이터베이스 프록시”에서 뭘 배우나요?

Deno와 Workers를 사용하여 기존 데이터베이스 또는 서버리스 데이터베이스에 연결하는 효율적인 데이터베이스 프록시를 만듭니다. 브라우저에서 직접 실행하는 실습 코드로 Edge Computing with Cloudflare Workers & Deno을(를) 배우며, 24/7 AI 튜터가 강의를 진행하면서 질문에 답변해줍니다.

Edge Computing with Cloudflare Workers & Deno을(를) 시작하는 데 경험이 필요한가요?

사전 경험은 필요하지 않습니다. CoddyKit의 Edge Computing with Cloudflare Workers & Deno은(는) 초급자부터 고급 학습자까지를 위해 구성되어 있으므로, 여기서 시작하거나 처음부터 시작할 수 있으며 자신의 속도대로 진행할 수 있습니다. 이것은 4개 중 3번째 강의입니다.

“Deno를 활용한 데이터베이스 프록시” 강의는 얼마나 걸리나요?

대부분의 CoddyKit 강의는 약 5~10분이 소요됩니다. 각 강의는 간결하고 인터랙티브하여 꾸준한 진행이 가능하며, 웹과 앱에서 중단한 부분부터 바로 시작할 수 있습니다.

이 Edge Computing with Cloudflare Workers & Deno 강의에서 코드를 작성하고 실행할 수 있나요?

네. 모든 Edge Computing with Cloudflare Workers & Deno 강의에는 내장 코드 에디터가 포함되어 있으므로, 브라우저에서 바로 실제 코드를 작성하고 실행한 후 즉시 AI 피드백을 받을 수 있습니다 — 로컬 설정이 필요 없습니다.

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