[适用于 JavaScript 的 Amazon SDK V3 API 参考指南](https://docs.amazonaws.cn/AWSJavaScriptSDK/v3/latest/)详细描述了 适用于 JavaScript 的 Amazon SDK 版本 3 (V3) 的所有 API 操作。

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。

# 有关特定服务客户端的说明
<a name="migrate-service-client-notes"></a>

## Amazon Lambda
<a name="aws-lambda-notes"></a>

 Lambda 调用响应类型在 v2 和 v3 中有所不同。

```
// v2
import { Lambda } from "@aws-sdk/client-lambda";
import AWS from "aws-sdk";

const lambda = new AWS.Lambda({ {{REGION}} });
const invoke = await lambda.invoke({
  FunctionName: "echo",
  Payload: JSON.stringify({ message: "hello" }),
}).promise();

// in v2, Lambda::invoke::Payload is automatically converted to string via a
// specific code customization.
const payloadIsString = typeof invoke.Payload === "string";
console.log("Invoke response payload type is string:", payloadIsString);

const payloadObject = JSON.parse(invoke.Payload);
console.log("Invoke response object", payloadObject);
```

```
// v3
const lambda = new Lambda({ {{REGION}} });
const invoke = await lambda.invoke({
  FunctionName: "echo",
  Payload: JSON.stringify({ message: "hello" }),
});

// in v3, Lambda::invoke::Payload is not automatically converted to a string.
// This is to reduce the number of customizations that create inconsistent behaviors.
const payloadIsByteArray = invoke.Payload instanceof Uint8Array;
console.log("Invoke response payload type is Uint8Array:", payloadIsByteArray);

// To maintain the old functionality, only one additional method call is needed:
// v3 adds a method to the Uint8Array called transformToString.
const payloadObject = JSON.parse(invoke.Payload.transformToString());
console.log("Invoke response object", payloadObject);
```

## Amazon SQS
<a name="amazon-sqs-notes"></a>

### MD5 校验和
<a name="md5-checksum"></a>

 要跳过对消息正文进行 MD5 校验和计算，请在配置对象上将 `md5` 设置为 *false*。否则，SDK 默认会为发送的消息计算校验和，并验证已检索消息的校验和。

```
// Example: Skip MD5 checksum in Amazon SQS
import { SQS } from "@aws-sdk/client-sqs";

new SQS({
  md5: false // note: only available in v3.547.0 and higher
});
```

在 Amazon SQS 操作中使用自定义 `QueueUrl` 作为输入参数时，v2 允许提供自定义 `QueueUrl` 来覆盖 Amazon SQS 客户端的默认端点。

### 多区域消息
<a name="multi-region-messages"></a>

 在 v3 中，您应为每个区域使用一个客户端。Amazon 区域应在客户端级别进行初始化，且不应在请求之间更改。

```
import { SQS } from "@aws-sdk/client-sqs";

const sqsClients = {
  "us-east-1": new SQS({ region: "us-east-1" }),
  "us-west-2": new SQS({ region: "us-west-2" }),
};

const queues = [
  { region: "us-east-1", url: "https://sqs.us-east-1.amazonaws.com/{AWS_ACCOUNT}/MyQueue" },
  { region: "us-west-2", url: "https://sqs.us-west-2.amazonaws.com/{AWS_ACCOUNT}/MyOtherQueue" },
];

for (const { region, url } of queues) {
  const params = {
    MessageBody: "Hello",
    QueueUrl: url,
  };
  await sqsClients[region].sendMessage(params);
}
```

### 自定义终端节点
<a name="custom-endpoint"></a>

 在 v3 中，当使用自定义端点（即与默认的 Amazon SQS 公有端点不同的端点）时，您应始终在 Amazon SQS 客户端中设置该端点，同时还需设置 ` QueueUrl` 字段。

```
import { SQS } from "@aws-sdk/client-sqs";

const sqs = new SQS({
  // client endpoint should be specified in v3 when not the default public SQS endpoint for your region.
  // This is required for versions <= v3.506.0
  // This is optional but recommended for versions >= v3.507.0 (a warning will be emitted)
  endpoint: "https://my-custom-endpoint:8000/",
});

await sqs.sendMessage({
  QueueUrl: "https://my-custom-endpoint:8000/1234567/MyQueue",
  Message: "hello",
});
```

 如果您未使用自定义端点，则无需在客户端设置 `endpoint`。

```
import { SQS } from "@aws-sdk/client-sqs";

const sqs = new SQS({
  region: "us-west-2",
});

await sqs.sendMessage({
  QueueUrl: "https://sqs.us-west-2.amazonaws.com/1234567/MyQueue",
  Message: "hello",
});
```