的版本 4 (V4) 适用于 .NET 的 AWS SDK 已经发布！

有关重大更改和迁移应用程序的信息，请参阅[迁移主题](https://docs.aws.amazon.com/sdk-for-net/v4/developer-guide/net-dg-v4.html)。

 [https://docs.aws.amazon.com/sdk-for-net/v4/developer-guide/net-dg-v4.html](https://docs.aws.amazon.com/sdk-for-net/v4/developer-guide/net-dg-v4.html)

本文属于机器翻译版本。若本译文内容与英语原文存在差异，则一律以英文原文为准。

# 使用适用于.NET 的 AWS 消息处理框架发布消息
<a name="msg-proc-fw-publish"></a>

.NET AWS 消息处理框架支持发布一种或多种消息类型、处理一种或多种消息类型，或者在同一个应用程序中同时处理这两种消息类型。

以下代码显示了向不同 AWS 服务发布不同消息类型的应用程序的配置。

```
var builder = WebApplication.CreateBuilder(args);

// Register the AWS Message Processing Framework for .NET
builder.Services.AddAWSMessageBus(builder =>
{
    // Register that you'll send messages of type ChatMessage to an existing queue
    builder.AddSQSPublisher<ChatMessage>("https://sqs.us-west-2.amazonaws.com/012345678910/MyAppProd");

    // Register that you'll publish messages of type OrderInfo to an existing SNS topic
    builder.AddSNSPublisher<OrderInfo>("arn:aws:sns:us-west-2:012345678910:MyAppProd");

    // Register that you'll publish messages of type FoodItem to an existing EventBridge bus
    builder.AddEventBridgePublisher<FoodItem>("arn:aws:events:us-west-2:012345678910:event-bus/default");
});
```

在启动期间注册框架后，`IMessagePublisher`将泛型注入到代码中。调用其`PublishAsync`方法来发布上面配置的任何消息类型。通用发布者将根据消息的类型确定要将消息路由到的目的地。

 在以下示例中，ASP.NET MVC 控制器接收来自用户的`ChatMessage`消息和`OrderInfo`事件，然后分别将其发布到亚马逊 SQS 和亚马逊 SNS。两种消息类型都可以使用上面配置的通用发布器发布。

```
[ApiController]
[Route("[controller]")]
public class PublisherController : ControllerBase
{
    private readonly IMessagePublisher _messagePublisher;

    public PublisherController(IMessagePublisher messagePublisher)
    {
        _messagePublisher = messagePublisher;
    }

    [HttpPost("chatmessage", Name = "Chat Message")]
    public async Task<IActionResult> PublishChatMessage([FromBody] ChatMessage message)
    {
        // Perform business and validation logic on the ChatMessage here.
        if (message == null)
        {
            return BadRequest("A chat message was not submitted. Unable to forward to the message queue.");
        }
        if (string.IsNullOrEmpty(message.MessageDescription))
        {
            return BadRequest("The MessageDescription cannot be null or empty.");
        }

        // Send the ChatMessage to SQS, using the generic publisher.
        await _messagePublisher.PublishAsync(message);

        return Ok();
    }

    [HttpPost("order", Name = "Order")]
    public async Task<IActionResult> PublishOrder([FromBody] OrderInfo message)
    {
        if (message == null)
        {
            return BadRequest("An order was not submitted.");
        }

        // Publish the OrderInfo to SNS, using the generic publisher.
        await _messagePublisher.PublishAsync(message);

        return Ok();
    }
}
```

为了将消息路由到相应的处理逻辑，框架使用称为*消息类型标识符*的元数据。默认情况下，这是消息的.NET 类型的全名，包括其程序集名称。如果你既要发送消息，又要处理消息，那么如果你跨项目共享消息对象的定义，这种机制就能很好地发挥作用。但是，如果在不同的命名空间中重新定义消息，或者您要与其他框架或编程语言交换消息，则可能需要覆盖消息类型标识符。

```
var builder = Host.CreateDefaultBuilder(args);

builder.ConfigureServices(services =>
{
    // Register the AWS Message Processing Framework for .NET
    services.AddAWSMessageBus(builder =>
    {
        // Register that you'll publish messages of type GreetingMessage to an existing queue
        builder.AddSQSPublisher<GreetingMessage>("https://sqs.us-west-2.amazonaws.com/012345678910/MyAppProd", "greetingMessage");
    });
});
```

## 特定服务的出版商
<a name="service-specific-publishers"></a>

上面显示的示例使用通用`IMessagePublisher`，它可以根据配置的消息类型发布到任何支持的 AWS 服务。该框架还为亚马逊 SQS、Amazon SNS 和亚马逊提供特定服务的发布商。 EventBridge这些特定的发布者公开的选项仅适用于该服务，并且可以使用`ISQSPublisher``ISNSPublisher`、和类型进行注入`IEventBridgePublisher`。

例如，向 SQS FIFO 队列发送消息时，必须设置相应的[消息组 ID](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/FIFO-key-terms.html)。以下代码再次显示了该`ChatMessage`示例，但现在使用`ISQSPublisher`来设置特定于 SQS 的选项。

```
public class PublisherController : ControllerBase
{
    private readonly ISQSPublisher _sqsPublisher;

    public PublisherController(ISQSPublisher sqsPublisher)
    {
        _sqsPublisher = sqsPublisher;
    }

    [HttpPost("chatmessage", Name = "Chat Message")]
    public async Task<IActionResult> PublishChatMessage([FromBody] ChatMessage message)
    {
        // Perform business and validation logic on the ChatMessage here
        if (message == null)
        {
            return BadRequest("A chat message was not submitted. Unable to forward to the message queue.");
        }
        if (string.IsNullOrEmpty(message.MessageDescription))
        {
            return BadRequest("The MessageDescription cannot be null or empty.");
        }

        // Send the ChatMessage to SQS using the injected ISQSPublisher, with SQS-specific options
        await _sqsPublisher.SendAsync(message, new SQSOptions
        {
            DelaySeconds = <delay-in-seconds>,
            MessageAttributes = <message-attributes>,
            MessageDeduplicationId = <message-deduplication-id>,
            MessageGroupId = <message-group-id>
        });

        return Ok();
    }
}
```

对于 SNS 和 EventBridge，也可以`IEventBridgePublisher`分别使用`ISNSPublisher`和。

```
await _snsPublisher.PublishAsync(message, new SNSOptions
{
    Subject = <subject>,
    MessageAttributes = <message-attributes>,
    MessageDeduplicationId = <message-deduplication-id>,
    MessageGroupId = <message-group-id>
});
```

```
await _eventBridgePublisher.PublishAsync(message, new EventBridgeOptions
{
    DetailType = <detail-type>,
    Resources = <resources>,
    Source = <source>,
    Time = <time>,
    TraceHeader = <trace-header>
});
```

默认情况下，给定类型的消息会发送到预先配置的目的地。但是，您可以使用特定于消息的发布者来覆盖单条消息的目的地。您还可以覆盖用于发布消息的底层 适用于 .NET 的 AWS SDK 客户端，这在需要根据目标更改角色或凭据的多租户应用程序中非常有用。

```
await _sqsPublisher.SendAsync(message, new SQSOptions
{
    OverrideClient = <override IAmazonSQS client>,
    QueueUrl = <override queue URL>
});
```