ASP.NET Core调用blobClient.UploadAsync()遇流关闭错误求助

向API发送multipart/form-data请求，请求包含IFormFile属性，控制器代码如下：

[Route("api/[controller]")]
public class HomeController : ControllerBase
{
    private readonly IBlobUploadService _blobUpload;

    public HomeController(IValidator<SubmitFileRequest> validator, IBlobUploadService blobUpload)
    {
        _blobUpload = blobUpload;
    }

    [HttpPost("SubmitFile")]
    public async Task<IActionResult> SubmitFile([FromForm]SubmitFileRequest request)
    {
        _blobUpload.UploadFile(request.File);

        return Ok();
    }
}

对应的Blob上传服务代码：

public interface IBlobUploadService
{
    void UploadFile(IFormFile file);
}

public class BlobUploadService : IBlobUploadService
{
    private string blobConnectionString = "my connection string";
    private string blobContainer = "my container";

    public async void UploadFile(IFormFile file)
    {
        BlobContainerClient container = new BlobContainerClient(blobConnectionString, blobContainer);

        var blobClient = container.GetBlobClient(file.FileName);

        await using (Stream? stream = file.OpenReadStream())
        {
            await blobClient.UploadAsync(stream);
        }
    }
}

执行await blobClient.UploadAsync(stream);时持续抛出异常：

System.AggregateException: 'Retry failed after 6 tries. Retry settings can be adjusted in ClientOptions.Retry or by configuring a custom retry policy in ClientOptions.RetryPolicy. (Error while copying content to a stream.) (Error while copying content to a stream.) (Error while copying content to a stream.) (Error while copying content to a stream.) (Error while copying content to a stream.) (Error while copying content to a stream.)'

Inner Exception 1: RequestFailedException: Error while copying content to a stream.

Inner Exception 2: HttpRequestException: Error while copying content to a stream.

Inner Exception 3: ObjectDisposedException: Cannot access a closed Stream.

更新：仅异步版本上传会触发异常，不使用await调用时可正常运行。

核心问题有两个：

1. async void的误用：UploadFile方法标记为async void，这种写法仅适用于事件处理程序，会导致调用方无法跟踪异步操作的完成状态，且异常无法被正确捕获和传播。
2. 未等待异步操作完成：控制器的SubmitFile方法中调用_blobUpload.UploadFile(request.File)时没有使用await，导致控制器方法提前返回，ASP.NET Core会立即释放请求上下文相关资源（包括IFormFile对应的流），此时异步上传操作还在进行，就会出现流已被释放的错误。

按以下步骤修改代码：

1. 修改服务接口和实现，将void改为Task
   接口和方法都要改为异步任务返回类型：

   public interface IBlobUploadService
   {
       Task UploadFile(IFormFile file);
   }
   
   public class BlobUploadService : IBlobUploadService
   {
       private string blobConnectionString = "my connection string";
       private string blobContainer = "my container";
   
       // 替换async void为async Task
       public async Task UploadFile(IFormFile file)
       {
           BlobContainerClient container = new BlobContainerClient(blobConnectionString, blobContainer);
   
           var blobClient = container.GetBlobClient(file.FileName);
   
           await using (Stream? stream = file.OpenReadStream())
           {
               await blobClient.UploadAsync(stream);
           }
       }
   }
   

2. 控制器中等待异步操作完成
   在SubmitFile方法中添加await关键字，确保上传操作完成后再返回响应：

   [HttpPost("SubmitFile")]
   public async Task<IActionResult> SubmitFile([FromForm]SubmitFileRequest request)
   {
       await _blobUpload.UploadFile(request.File);
   
       return Ok();
   }
   

3. 可选：重置流位置（适配重试机制）
   如果Blob客户端的重试机制需要重新读取流，可在上传前重置流的位置到起始处，避免重试时流已到末尾：

   await using (Stream? stream = file.OpenReadStream())
   {
       stream.Position = 0; // 重置流位置
       await blobClient.UploadAsync(stream);
   }
   

内容的提问来源于stack exchange，提问作者JackFord