Untappd MCP Server using Azure Functions

Okay, here's an example of a minimal, complete, and practical (MCP) Azure Function written in F# that demonstrates a simple HTTP trigger. I'll break it down with explanations. ```fsharp namespace MyAzureFunction open Microsoft.AspNetCore.Mvc open Microsoft.Azure.WebJobs open Microsoft.Azure.WebJobs.Extensions.Http open Microsoft.AspNetCore.Http open Microsoft.Extensions.Logging module HelloFunction = [<FunctionName("Hello")>] let Run ( [<HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)>] req: HttpRequest, log: ILogger ) = log.LogInformation "C# HTTP trigger function processed a request." let name = match req.Query.["name"] with | ValueSome n -> n | ValueNone -> match System.IO.StreamReader(req.Body).ReadToEndAsync().Result with | body when not (String.IsNullOrEmpty body) -> body | _ -> "Azure Function" let responseMessage = sprintf "Hello, %s. This HTTP triggered function executed successfully." name ActionResult(OkObjectResult responseMessage) ``` **Explanation:** 1. **Namespace:** `namespace MyAzureFunction` This organizes your code. Choose a meaningful name. 2. **`open` Statements:** These bring in the necessary libraries. Crucially: * `Microsoft.AspNetCore.Mvc`: For `IActionResult` (the return type) and `OkObjectResult`. * `Microsoft.Azure.WebJobs`: The core Azure Functions library. * `Microsoft.Azure.WebJobs.Extensions.Http`: For HTTP trigger functionality. * `Microsoft.AspNetCore.Http`: For the `HttpRequest` object. * `Microsoft.Extensions.Logging`: For logging. 3. **Module:** `module HelloFunction` F# code is typically organized into modules. 4. **`[<FunctionName("Hello")>]`:** This *attribute* is **essential**. It tells Azure Functions the name of your function. This is the name you'll use in the Azure portal or when deploying. Change `"Hello"` to whatever you want to call your function. 5. **`let Run (...) = ...`:** This defines the function itself. `Run` is the standard name for the entry point. 6. **Function Parameters:** * `[<HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)>] req: HttpRequest`: This is the HTTP trigger. * `[<HttpTrigger(...)]`: This attribute configures the trigger. * `AuthorizationLevel.Anonymous`: Means anyone can call the function without authentication. Other options are `Function` (requires a function key) and `Admin` (requires an admin key). * `"get", "post"`: Specifies that the function will respond to both GET and POST requests. You can add other HTTP methods like `"put"`, `"delete"`, etc. * `Route = null`: This means the function is triggered directly by the function name. If you set `Route = "myroute/{id}"`, the function would be triggered by a URL like `/api/myroute/123`. `null` is the simplest option for a basic example. * `req: HttpRequest`: This is the HTTP request object. It contains information about the request, such as headers, query parameters, and the request body. * `log: ILogger`: This is the logger. Use it to write information to the Azure Functions logs. Very helpful for debugging. 7. **Function Body:** * `log.LogInformation "C# HTTP trigger function processed a request."`: Logs a message to the console. This will appear in the Azure Functions logs. * **Name Extraction:** This part tries to get the `name` parameter from either the query string or the request body. * `req.Query.["name"]`: Tries to get the `name` parameter from the query string (e.g., `?name=John`). `req.Query` is a dictionary-like structure. * `ValueSome n -> n`: If the `name` parameter is found in the query string, its value is assigned to `n`. * `ValueNone -> ...`: If the `name` parameter is *not* found in the query string, the code proceeds to read the request body. * `System.IO.StreamReader(req.Body).ReadToEndAsync().Result`: Reads the entire request body as a string. **Important:** Using `.Result` is generally discouraged in asynchronous code because it can lead to deadlocks. However, in the context of an Azure Function, it's often acceptable for simplicity, *especially* in F#. For more complex scenarios, you'd want to use `async` and `await` properly. * `body when not (String.IsNullOrEmpty body) -> body`: If the request body is not empty, its content is used as the `name`. * `_ -> "Azure Function"`: If neither the query string nor the request body contains a `name`, the default value "Azure Function" is used. * `let responseMessage = sprintf "Hello, %s. This HTTP triggered function executed successfully." name`: Creates the response message using `sprintf` (string formatting). * `ActionResult(OkObjectResult responseMessage)`: Creates an `OkObjectResult` (an HTTP 200 OK response) with the response message as the body. The `ActionResult` type is used to wrap the result. This is how you return a response from an Azure Function. **How to Use It:** 1. **Create an Azure Functions Project:** In Visual Studio or VS Code with the Azure Functions extension, create a new F# Azure Functions project. Choose the "HTTP trigger" template. 2. **Replace the Code:** Replace the contents of the generated `.fs` file with the code above. 3. **Run Locally:** Run the function locally. The Azure Functions runtime will start and tell you the URL to access your function. 4. **Test:** * **GET Request (with query parameter):** Open a browser and go to `http://localhost:7071/api/Hello?name=YourName` (replace `7071` with the port your function is running on). You should see "Hello, YourName. This HTTP triggered function executed successfully." * **GET Request (without query parameter):** Go to `http://localhost:7071/api/Hello`. You should see "Hello, Azure Function. This HTTP triggered function executed successfully." * **POST Request (with body):** Use a tool like `curl` or Postman to send a POST request to `http://localhost:7071/api/Hello` with a request body containing the name (e.g., `"MyName"`). The response should be "Hello, MyName. This HTTP triggered function executed successfully." 5. **Deploy to Azure:** Deploy your function to Azure using Visual Studio, VS Code, or the Azure CLI. **Key Improvements and Considerations:** * **Error Handling:** This example lacks proper error handling. In a real-world function, you should handle exceptions and return appropriate error responses (e.g., `BadRequestObjectResult`, `InternalServerErrorResult`). * **Asynchronous Operations:** For more complex operations (especially I/O), use `async` and `await` to avoid blocking the thread. This is crucial for scalability. The `.Result` call is a shortcut for this example, but should be avoided in production code where possible. * **Dependency Injection:** For larger functions, use dependency injection to manage dependencies (e.g., configuration, database connections). Azure Functions supports dependency injection. * **Configuration:** Use the Azure Functions configuration system to store settings (e.g., connection strings, API keys). * **Logging:** Use the `ILogger` interface extensively to log information, warnings, and errors. This is essential for debugging and monitoring. * **Idempotency:** If your function performs operations that should only be executed once (e.g., processing payments), ensure that it's idempotent. * **Testing:** Write unit tests to verify the logic of your function. **Chinese Translation of the Explanation:** **F# 中的一个最小、完整、实用的 (MCP) Azure 函数示例** 这是一个用 F# 编写的最小、完整、实用的 (MCP) Azure 函数示例，它演示了一个简单的 HTTP 触发器。 我将分解并解释它。 ```fsharp namespace MyAzureFunction open Microsoft.AspNetCore.Mvc open Microsoft.Azure.WebJobs open Microsoft.Azure.WebJobs.Extensions.Http open Microsoft.AspNetCore.Http open Microsoft.Extensions.Logging module HelloFunction = [<FunctionName("Hello")>] let Run ( [<HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)>] req: HttpRequest, log: ILogger ) = log.LogInformation "C# HTTP 触发器函数处理了一个请求。" let name = match req.Query.["name"] with | ValueSome n -> n | ValueNone -> match System.IO.StreamReader(req.Body).ReadToEndAsync().Result with | body when not (String.IsNullOrEmpty body) -> body | _ -> "Azure Function" let responseMessage = sprintf "你好，%s。 此 HTTP 触发函数已成功执行。" name ActionResult(OkObjectResult responseMessage) ``` **解释：** 1. **命名空间：** `namespace MyAzureFunction` 这组织你的代码。 选择一个有意义的名称。 2. **`open` 语句：** 这些引入了必要的库。 至关重要的是： * `Microsoft.AspNetCore.Mvc`：用于 `IActionResult`（返回类型）和 `OkObjectResult`。 * `Microsoft.Azure.WebJobs`：核心 Azure Functions 库。 * `Microsoft.Azure.WebJobs.Extensions.Http`：用于 HTTP 触发器功能。 * `Microsoft.AspNetCore.Http`：用于 `HttpRequest` 对象。 * `Microsoft.Extensions.Logging`：用于日志记录。 3. **模块：** `module HelloFunction` F# 代码通常组织成模块。 4. **`[<FunctionName("Hello")>]`：** 这个*属性*是**必不可少的**。 它告诉 Azure Functions 你的函数的名称。 这是你将在 Azure 门户中使用或部署时使用的名称。 将 `"Hello"` 更改为你想要调用的任何名称。 5. **`let Run (...) = ...`：** 这定义了函数本身。 `Run` 是入口点的标准名称。 6. **函数参数：** * `[<HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)>] req: HttpRequest`：这是 HTTP 触发器。 * `[<HttpTrigger(...)]`：此属性配置触发器。 * `AuthorizationLevel.Anonymous`：表示任何人都可以调用该函数而无需身份验证。 其他选项是 `Function`（需要函数密钥）和 `Admin`（需要管理员密钥）。 * `“get”, “post”`：指定该函数将响应 GET 和 POST 请求。 你可以添加其他 HTTP 方法，例如 `"put"`、`"delete"` 等。 * `Route = null`：这意味着该函数由函数名称直接触发。 如果你设置 `Route = "myroute/{id}"`，则该函数将由类似 `/api/myroute/123` 的 URL 触发。 `null` 是基本示例的最简单选项。 * `req: HttpRequest`：这是 HTTP 请求对象。 它包含有关请求的信息，例如标头、查询参数和请求正文。 * `log: ILogger`：这是记录器。 使用它将信息写入 Azure Functions 日志。 对调试非常有帮助。 7. **函数体：** * `log.LogInformation "C# HTTP 触发器函数处理了一个请求。"`：将消息记录到控制台。 这将出现在 Azure Functions 日志中。 * **名称提取：** 这部分尝试从查询字符串或请求正文中获取 `name` 参数。 * `req.Query.["name"]`：尝试从查询字符串中获取 `name` 参数（例如，`?name=John`）。 `req.Query` 是一个类似字典的结构。 * `ValueSome n -> n`：如果在查询字符串中找到 `name` 参数，则将其值分配给 `n`。 * `ValueNone -> ...`：如果在查询字符串中*未*找到 `name` 参数，则代码继续读取请求正文。 * `System.IO.StreamReader(req.Body).ReadToEndAsync().Result`：将整个请求正文读取为字符串。 **重要提示：** 通常不鼓励在异步代码中使用 `.Result`，因为它可能导致死锁。 但是，在 Azure Function 的上下文中，为了简单起见，通常是可以接受的，*尤其是在 F# 中*。 对于更复杂的场景，你将需要正确使用 `async` 和 `await`。 * `body when not (String.IsNullOrEmpty body) -> body`：如果请求正文不为空，则其内容将用作 `name`。 * `_ -> "Azure Function"`：如果查询字符串和请求正文都不包含 `name`，则使用默认值 "Azure Function"。 * `let responseMessage = sprintf "你好，%s。 此 HTTP 触发函数已成功执行。" name`：使用 `sprintf`（字符串格式化）创建响应消息。 * `ActionResult(OkObjectResult responseMessage)`：创建一个 `OkObjectResult`（HTTP 200 OK 响应），并将响应消息作为正文。 `ActionResult` 类型用于包装结果。 这是你从 Azure Function 返回响应的方式。 **如何使用它：** 1. **创建 Azure Functions 项目：** 在 Visual Studio 或带有 Azure Functions 扩展的 VS Code 中，创建一个新的 F# Azure Functions 项目。 选择“HTTP 触发器”模板。 2. **替换代码：** 将生成的 `.fs` 文件的内容替换为上面的代码。 3. **在本地运行：** 在本地运行该函数。 Azure Functions 运行时将启动并告诉你访问你的函数的 URL。 4. **测试：** * **GET 请求（带查询参数）：** 打开浏览器并转到 `http://localhost:7071/api/Hello?name=YourName`（将 `7071` 替换为你的函数正在运行的端口）。 你应该看到“你好，YourName。 此 HTTP 触发函数已成功执行。” * **GET 请求（不带查询参数）：** 转到 `http://localhost:7071/api/Hello`。 你应该看到“你好，Azure Function。 此 HTTP 触发函数已成功执行。” * **POST 请求（带正文）：** 使用 `curl` 或 Postman 等工具向 `http://localhost:7071/api/Hello` 发送 POST 请求，请求正文包含名称（例如，`"MyName"`）。 响应应为“你好，MyName。 此 HTTP 触发函数已成功执行。” 5. **部署到 Azure：** 使用 Visual Studio、VS Code 或 Azure CLI 将你的函数部署到 Azure。 **关键改进和注意事项：** * **错误处理：** 此示例缺少适当的错误处理。 在实际函数中，你应该处理异常并返回适当的错误响应（例如，`BadRequestObjectResult`、`InternalServerErrorResult`）。 * **异步操作：** 对于更复杂的操作（尤其是 I/O），请使用 `async` 和 `await` 以避免阻塞线程。 这对于可伸缩性至关重要。 `.Result` 调用是此示例的快捷方式，但在可能的情况下应避免在生产代码中使用。 * **依赖注入：** 对于更大的函数，请使用依赖注入来管理依赖项（例如，配置、数据库连接）。 Azure Functions 支持依赖注入。 * **配置：** 使用 Azure Functions 配置系统来存储设置（例如，连接字符串、API 密钥）。 * **日志记录：** 广泛使用 `ILogger` 接口来记录信息、警告和错误。 这对于调试和监控至关重要。 * **幂等性：** 如果你的函数执行应仅执行一次的操作（例如，处理付款），请确保它是幂等的。 * **测试：** 编写单元测试以验证你的函数的逻辑。 This should give you a solid starting point for building Azure Functions in F#. Let me know if you have any more questions.