在@aws-sdk/client-lambda v3中解码InvokeCommandOutput.Payload遇错求助

我在Express.js + TypeScript环境中调用Lambda函数的代码如下：

import type {InvokeCommandOutput} from '@aws-sdk/client-lambda';
import {InvokeCommand} from '@aws-sdk/client-lambda';

const command = new InvokeCommand({
  FunctionName: this.client_name,
  InvocationType: 'RequestResponse',
  Payload: Buffer.from(JSON.stringify(event)),
});
const response: InvokeCommandOutput = await this.client.send(command);
const payLoad = response.Payload;

if (payLoad != undefined) {
  return response.Payload;
}

我期望从Lambda函数返回的InvokeCommandOutput.Payload中得到如下格式的响应：

{
  "challenge_name": "CHALLENGE_NAME",
  "session":  "session string"
}

我使用的是AWS SDK v3的Lambda客户端。

尝试过AWS官方示例以及SDK中的toUtf8和fromUtf8函数解码Uint8Array，但出现以下错误：

{"errorType":"TypeError","errorMessage":"The \"key\" argument must be of type string or an instance of ArrayBuffer, Buffer, TypedArray, DataView, KeyObject, or CryptoKey. Received null","trace":["TypeError [ERR_INVALID_ARG_TYPE]: The \"key\" argument must be of type string or an instance of ArrayBuffer, Buffer, TypedArray, DataView, KeyObject, or CryptoKey. Received null","    at new NodeError (node:internal/errors:372:5)","    at prepareSecretKey (node:internal/crypto/keys:580:11)","    at new Hmac (node:internal/crypto/hash:132:9)","    at createHmac (node:crypto:162:10)","    at AuthService.initiateAuth (/var/task/main.js:57511:48)","    at processTicksAndRejections (node:internal/process/task_queues:96:5)","    at async Runtime.handler (/var/task/main.js:34:9)"]}

使用的是AWS SDK v3中Lambda客户端的InvokeCommand类。

我把这段代码：

if(payLoad != undefined){
    console.info(payLoad);
    return payLoad;
}

替换为：

if(payLoad != undefined){
    console.info(payLoad);
    return JSON.parse(Buffer.from(payLoad).toString());
}

得到的Payload输出如下：

Uint8Array(777) [
  123,  34, 101, 114, 114, 111, 114,  84, 121, 112, 101,  34,
   58,  34,  84, 121, 112, 101,  69, 114, 114, 111, 114,  34,
   44,  34, 101, 114, 114, 111, 114,  77, 101, 115, 115,  97,
  103, 101,  34,  58,  34,  84, 104, 101,  32,  92,  34, 107,
  101, 121,  92,  34,  32,  97, 114, 103, 117, 109, 101, 110,
  116,  32, 109, 117, 115, 116,  32,  98, 101,  32, 111, 102,
   32, 116, 121, 112, 101,  32, 115, 116, 114, 105, 110, 103,
   32, 111, 114,  32,  97, 110,  32, 105, 110, 115, 116,  97,
  110,  99, 101,  32,
  ... 677 more items
]

但仍然出现相同错误，说明Payload解码存在问题：

'The "key" argument must be of type string or an instance of ArrayBuffer, Buffer, TypedArray, DataView, KeyObject, or CryptoKey. Received null'

内容的提问来源于stack exchange，提问作者James Nganga