Edge Computing with Cloudflare Workers & Deno · 课时

将 Deno 与边缘存储集成

开发可与 Cloudflare KV 和 Durable Objects 交互的 Deno 函数，以管理数据

将 Deno 与边缘存储集成 是 CoddyKit 上的免费 Edge Computing with Cloudflare Workers & Deno 课时。这是第 3 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 Edge Computing with Cloudflare Workers & Deno 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Edge Computing with Cloudflare Workers & Deno 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

Deno & Edge Storage Integration

Welcome! In previous lessons, we learned about Cloudflare KV and Durable Objects for storing data at the edge. Now, let's explore how Deno applications can interact with these powerful edge storage solutions.

Since Deno typically runs outside the Cloudflare Workers environment, we'll focus on how Deno can act as a client, communicating with Cloudflare Workers that then manage interactions with KV and Durable Objects.

Deno's Role: The Proxy Pattern

Deno applications, whether running locally or deployed on platforms like Deno Deploy, don't directly access Cloudflare's KV or Durable Objects.

Instead, Deno acts as a client, making standard HTTP requests to a Cloudflare Worker. This Worker then serves as a proxy, handling the actual interactions with KV or Durable Objects on the Cloudflare edge network.

Deno App: Sends HTTP requests (e.g., GET, POST).
Cloudflare Worker: Receives requests, accesses KV/DO, and sends responses.

Cloudflare KV: Quick Review

Remember, Cloudflare KV is a global, low-latency key-value store perfect for caching, configuration, and user preferences.

Workers interact with KV using simple APIs like KV.put() to store data and KV.get() to retrieve it. Our Deno client will send requests to a Worker, which will then use these KV operations.

Storing Data from Deno to KV

To store data from your Deno application into a Cloudflare KV namespace, the process typically involves these steps:

Your Deno app sends an HTTP POST request to a specific endpoint on your Cloudflare Worker.
The Worker receives this request, extracts the key and value from the request body.
The Worker uses its bound KV namespace (e.g., MY_KV.put(key, value)) to store the data.
The Worker sends an HTTP response back to the Deno app, confirming the operation.

Worker Proxy for KV Write

Here's a simple Cloudflare Worker that accepts POST requests to store data in a KV namespace named MY_KV. Remember to bind MY_KV in your wrangler.toml.

Try running this example:

export default {
  async fetch(request, env) {
    const url = new URL(request.url);
    if (request.method === "POST" && url.pathname === "/put") {
      try {
        const { key, value } = await request.json();
        if (!key || !value) {
          return new Response("Missing key or value", { status: 400 });
        }
        await env.MY_KV.put(key, value);
        return new Response(`Stored key: ${key}`, { status: 200 });
      } catch (error) {
        return new Response(`Error: ${error.message}`, { status: 500 });
      }
    }
    return new Response("Not found", { status: 404 });
  },
};

Deno Client Writing to KV

Now, let's create a Deno script that acts as the client. It will send a JSON payload to our Cloudflare Worker proxy to store data in KV.

You'll need to replace YOUR_WORKER_URL with your deployed Worker's URL.

Try running this example:

// main.ts
const workerUrl = "YOUR_WORKER_URL"; // e.g., "https://your-worker.your-account.workers.dev"

async function putDataToKv(key: string, value: string) {
  try {
    const response = await fetch(`${workerUrl}/put`, {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
      },
      body: JSON.stringify({ key, value }),
    });

    if (response.ok) {
      console.log(`Successfully stored: ${await response.text()}`);
    } else {
      console.error(`Failed to store: ${response.status} ${response.statusText}`);
      console.error(await response.text());
    }
  } catch (error) {
    console.error("Network error:", error.message);
  }
}

// Example usage:
if (import.meta.main) {
  await putDataToKv("myKey", "myValue from Deno!");
  await putDataToKv("anotherKey", "Hello Edge!");
}

Retrieving Data from KV to Deno

Reading data follows a similar proxy pattern:

Your Deno app sends an HTTP GET request to your Cloudflare Worker, usually including the key in the URL path or query parameters.
The Worker receives this request, extracts the key.
The Worker uses env.MY_KV.get(key) to retrieve the data.
The Worker sends the retrieved value (or an error) as an HTTP response back to the Deno app.

Worker Proxy for KV Read

Let's add a GET endpoint to our Worker to fetch data from KV. This could be integrated into the previous Worker example.

Try running this example:

export default {
  async fetch(request, env) {
    const url = new URL(request.url);
    // Handle POST for putting data
    if (request.method === "POST" && url.pathname === "/put") {
      try {
        const { key, value } = await request.json();
        if (!key || !value) {
          return new Response("Missing key or value", { status: 400 });
        }
        await env.MY_KV.put(key, value);
        return new Response(`Stored key: ${key}`, { status: 200 });
      } catch (error) {
        return new Response(`Error: ${error.message}`, { status: 500 });
      }
    }
    // Handle GET for getting data
    if (request.method === "GET" && url.pathname.startsWith("/get/")) {
      const key = url.pathname.substring(5); // "/get/myKey" -> "myKey"
      if (!key) {
        return new Response("Missing key", { status: 400 });
      }
      const value = await env.MY_KV.get(key);
      if (value === null) {
        return new Response("Key not found", { status: 404 });
      }
      return new Response(value, { status: 200 });
    }
    return new Response("Not found", { status: 404 });
  },
};

Deno Client Reading from KV

Here's a Deno script to fetch data from the Worker's GET endpoint. This assumes you've already stored "myKey" and "anotherKey" using the previous Deno script.

Try running this example:

// main.ts
const workerUrl = "YOUR_WORKER_URL"; // e.g., "https://your-worker.your-account.workers.dev"

async function getDataFromKv(key: string) {
  try {
    const response = await fetch(`${workerUrl}/get/${key}`);

    if (response.ok) {
      console.log(`Value for '${key}': ${await response.text()}`);
    } else {
      console.error(`Failed to get data: ${response.status} ${response.statusText}`);
      console.error(await response.text());
    }
  } catch (error) {
    console.error("Network error:", error.message);
  }
}

// Example usage:
if (import.meta.main) {
  await getDataFromKv("myKey");
  await getDataFromKv("anotherKey");
  await getDataFromKv("nonExistentKey"); // Will show "Key not found"
}

Deno & Durable Objects

Durable Objects provide consistent state for individual users or entities at the edge. Just like KV, Deno applications interact with Durable Objects indirectly through a Cloudflare Worker.

The Worker will instantiate or get a reference to a Durable Object, call its methods, and then return the result to the Deno client. This pattern allows your Deno app to leverage stateful edge logic.

Deno App: Sends requests to a Worker.
Cloudflare Worker: Routes to a specific Durable Object instance, invokes methods.
Durable Object: Manages its internal state and responds.

Edge Storage Integration Check

Considering how Deno applications integrate with Cloudflare's edge storage services (KV and Durable Objects), what is the primary mechanism for this interaction?

Integrating Deno & Edge Storage

Great job! In this lesson, you've learned how to integrate Deno applications with Cloudflare KV and Durable Objects.

Deno acts as a client, sending HTTP requests.
Cloudflare Workers function as proxies, handling the actual storage operations.
This pattern allows Deno apps to leverage the power of edge data persistence securely and efficiently.

This integration opens up possibilities for building powerful full-stack applications with Deno on the client/server and Workers managing edge data.

常见问题解答

「将 Deno 与边缘存储集成」课时是免费的吗？

是的 — 「将 Deno 与边缘存储集成」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Edge Computing with Cloudflare Workers & Deno 课程的其余内容，请升级到 CoddyKit PRO。 Edge Computing with Cloudflare Workers & Deno 课程共包含 4 节课。

「将 Deno 与边缘存储集成」这节课中我会学到什么？

开发可与 Cloudflare KV 和 Durable Objects 交互的 Deno 函数，以管理数据你通过在浏览器中直接运行的动手代码来练习 Edge Computing with Cloudflare Workers & Deno，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 Edge Computing with Cloudflare Workers & Deno 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Edge Computing with Cloudflare Workers & Deno 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 3 节课，共 4 节。

「将 Deno 与边缘存储集成」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 Edge Computing with Cloudflare Workers & Deno 课中编写并运行代码吗？

能。每节 Edge Computing with Cloudflare Workers & Deno 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

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