在Microsoft Power Automate自定义连接器中实现Autodesk APS上传遇阻求助

我正在Microsoft Power Automate中创建自定义连接器，对接Autodesk的Data Management API，但卡在了文档中的步骤5——直接上传至签名S3 URL。

我已在Postman中验证其余流程均可正常运行；也通过shell脚本的curl命令测试了步骤5，确认签名URL生成正常且上传能顺利完成。

我尝试了两种在Power Automate中执行上传的方式：

方法1：使用HTTP操作 #

传入签名URL，请求方法为PUT，请求体放入文件内容，操作的代码视图如下：

{
  "type": "Http",
  "inputs": {
    "uri": "[REDACTED SIGNED URL]",
    "method": "PUT",
    "body": "@body('Get_file_content')"
  },
  "runAfter": {
    "Upload_file_to_S3_signed_URL": [
      "Succeeded"
    ]
  },
  "runtimeConfiguration": {
    "contentTransfer": {
      "transferMode": "Chunked"
    }
  }
}

执行后出现错误：

InvalidProtocolResponse
The response to partial content upload initiating request is not valid. The response to initiating partial content upload request must contain a valid location header.

方法2：构建专用自定义连接器 #

因S3上传的主机名与其他Autodesk API不同，我构建了专用自定义连接器，其swagger JSON如下：

swagger: '2.0'
info:
  title: APS S3 Signed URL Uploader
  description: Direct upload to S3 signed URL generated by the Data Management API.
  version: '1.0'
host: com-autodesk-oss-direct-upload.s3-accelerate.amazonaws.com
basePath: /
schemes:
  - https
consumes:
  - application/octet-stream
produces:
  - application/json
paths:
  /upload:
    put:
      summary: Upload file to S3 signed URL
      operationId: UploadToURL
      parameters:
        - name: signedURL
          in: query
          required: true
          type: string
          description: Signed URL generated by the Data Management API.
        - name: fileContent
          in: body
          required: true
          schema:
            type: string
            format: binary
            description: Binary file content to upload.
      responses:
        '200':
          description: Upload successful
          schema:
            type: object
            properties:
              message:
                type: string
                example: File uploaded successfully.
        '400':
          description: Bad Request
        '500':
          description: Internal Server Error
securityDefinitions: {}

此方式返回403错误，响应体如下：

<?xml version="1.0" encoding="UTF-8"?>
<Error><Code>AccessDenied</Code><Message>Access Denied</Message><RequestId>V48YVK8JA62E8GX3</RequestId><HostId>z6CEun8FVfqQEB1ostuWqeWJUeEMtd9L0c4X5NsS70akh7sMSL6S3uC/I53IikjDD6waL5MjM/0=</HostId></Error>

我并非专业开发人员，若有明显疏漏还请见谅，恳请提供解决方向。

内容的提问来源于stack exchange，提问作者Zulphide