再次“不允许同步操作”

Question

我已阅读主题：ASP.NET Core : Synchronous operations are disallowed. Call WriteAsync or set AllowSynchronousIO to true instead 但对于我的情况，我无法理解，如何解决它：

我有控制器方法：

    public async Task<IActionResult> Upload()
    {
        var boundary = MultipartRequestHelper.GetBoundary(MediaTypeHeaderValue.Parse(Request.ContentType), _defaultFormOptions.MultipartBoundaryLengthLimit);
        var reader = new MultipartReader(boundary.ToString(), HttpContext.Request.Body);

        var section = await reader.ReadNextSectionAsync();
        List<FileApi> uploadedFiles = new List<FileApi>();

        while (section != null)
        {
            ContentDispositionHeaderValue contentDisposition;
            var hasContentDispositionHeader = ContentDispositionHeaderValue.TryParse(section.ContentDisposition, out contentDisposition);

            if (hasContentDispositionHeader)
            {
                if (MultipartRequestHelper.HasFileContentDisposition(contentDisposition))
                {
                    var fileDto = await _zendeskManageFileService.UploadFileAsync(contentDisposition.FileName.ToString(), section.Body);
                    uploadedFiles.Add(_mapper.Map<FileApi>(fileDto));
                }
                else if (MultipartRequestHelper.HasFormDataContentDisposition(contentDisposition))
                {
                    var errorNoFile = new ErrorResponse
                    {
                        Error = new Error
                        {
                            Code = "NoFile",
                            Message = $"Expected a file, no form data content",
                        }
                    };

                    return BadRequest(errorNoFile);
                }
            }
            section = await reader.ReadNextSectionAsync();
        }

        return Created("", uploadedFiles);
    }

当有 2 个或更多文件时，我在线上的第二个文件出现异常：

var fileDto = await _zendeskManageFileService.UploadFileAsync(contentDisposition.FileName.ToString(), section.Body);

UploadFileAsync 的代码如下：

    public async Task<FileDto> UploadFileAsync(string filename, Stream stream)
    {
        if (stream.Position != 0)
            stream.Position = 0;

        var upload = await _zendeskClient.Attachments.UploadAsync(filename, stream);
        FileDto fileDto = new FileDto
        {
            Id = upload.Id,
            ContentType = upload.Attachment.ContentType,
            Token = upload.Token,
            ContentUrl = upload.Attachment.ContentUrl,
            FileName = upload.Attachment.FileName,
            Size = upload.Attachment.Size
        };

        return fileDto;
    }

    public async Task<Upload> UploadAsync(
        string fileName, 
        Stream inputStream, 
        string token = null,
        CancellationToken cancellationToken = default(CancellationToken))
    {
        var attachmentResponse = await ExecuteRequest(async (client, canToken) => 
                await client.PostAsBinaryAsync(
                    UploadsResourceUri + $"?filename={fileName}&token={token}",
                    inputStream,
                    fileName,
                    canToken)
                .ConfigureAwait(false), 
                "UploadAsync",
                cancellationToken)
            .ThrowIfUnsuccessful("attachments#upload-files", HttpStatusCode.Created)
            .ReadContentAsAsync<UploadResponse>();

        return attachmentResponse.Upload;
    }

    public static async Task<HttpResponseMessage> PostAsBinaryAsync(
        this HttpClient client,
        string requestUri,
        Stream inputStream,
        string fileName,
        CancellationToken cancellationToken = default(CancellationToken))
    {
        using (var stream = new MemoryStream())
        {
            inputStream.CopyTo(stream);

            using (var content = new ByteArrayContent(stream.ToArray()))
            {
                content.Headers.ContentType = new MediaTypeHeaderValue("application/binary");

                return await client.PostAsync(
                        requestUri, 
                        content, 
                        cancellationToken)
                    .ConfigureAwait(false);
            }
        }
    }

    internal static async Task<T> ReadContentAsAsync<T>(
        this Task<HttpResponseMessage> response,
        JsonConverter converter = null)
        where T : class
    {
        var unwrappedResponse = await response;

        if (unwrappedResponse == null)
            return null;

        if (converter == null)
        {
            return await unwrappedResponse
                .Content
                .ReadAsAsync<T>();
        }

        return await unwrappedResponse
            .Content
            .ReadAsAsync<T>(converter);
    }

    protected async Task<HttpResponseMessage> ExecuteRequest(
        Func<HttpClient, CancellationToken, Task<HttpResponseMessage>> requestBodyAccessor,
        string scope,
        CancellationToken cancellationToken = default(CancellationToken))
    {
        using (LoggerScope(Logger, scope))
        using (var client = ApiClient.CreateClient())
        {
            return await requestBodyAccessor(client, cancellationToken);
        }
    }

我尝试创建和使用属性来设置AllowSynchronousIO = true

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
public class AllowSynchronousIOAttribute : ActionFilterAttribute
{
    public AllowSynchronousIOAttribute()
    {
    }

    public override void OnResultExecuting(ResultExecutingContext context)
    {
        var syncIOFeature = context.HttpContext.Features.Get<IHttpBodyControlFeature>();
        if (syncIOFeature != null)
        {
            syncIOFeature.AllowSynchronousIO = true;
        }
    }
}

但这无济于事。我的情况如何解决这个问题？

堆栈错误是：

System.InvalidOperationException：同步操作是 不允许。改为调用 ReadAsync 或将 AllowSynchronousIO 设置为 true。 在 Microsoft.AspNetCore.Server.IIS.Core.HttpRequestStream.Read（字节 [] 缓冲区，Int32 偏移量，Int32 计数）在 Microsoft.AspNetCore.Server.IIS.Core.WrappingStream.Read（字节 [] 缓冲区，Int32 偏移量，Int32 计数）在 Microsoft.AspNetCore.WebUtilities.BufferedReadStream.EnsureBuffered（Int32 minCount) 在 Microsoft.AspNetCore.WebUtilities.MultipartReaderStream.Read（字节 [] 缓冲区，Int32 偏移量，Int32 计数）在 System.IO.Stream.CopyTo（流目标，Int32 bufferSize）在 System.IO.Stream.CopyTo（流目的地）在 ZendeskApi.Client.Extensions.HttpRequestExtensions.PostAsBinaryAsync(HttpClient 客户端，字符串 requestUri，流 inputStream，字符串文件名， CancellationToken 取消令牌）在 C:\www\TMS\Libraries\ZendeskApi.Client\Extensions\HttpRequestExtensions.cs:line 75 在 ZendeskApi.Client.Resources.AttachmentsResource.c__DisplayClass4_0.d.MoveNext() 在 C:\www\TMS\Libraries\ZendeskApi.Client\Resources\AttachmentsResource.cs:line 45 --- 从先前抛出异常的位置结束堆栈跟踪 --- 在 ZendeskApi.Client.Resources.AbstractBaseResource1.ExecuteRequest(Func3 requestBodyAccessor，字符串范围，CancellationToken 取消令牌）在 C:\www\TMS\Libraries\ZendeskApi.Client\Resources\AbstractBaseResource.cs:line 41 在 ZendeskApi.Client.Extensions.HttpResponseExtensions.ThrowIfUnsuccessful（预期任务1 response, String helpDocLink, Nullable1，字符串 helpDocLinkPrefix) 在 C:\www\TMS\Libraries\ZendeskApi.Client\Extensions\HttpResponseExtensions.cs:line 90 在 ZendeskApi.Client.Extensions.HttpResponseExtensions.ReadContentAsAsync[T](Task`1 响应，JsonConverter 转换器）在 C:\www\TMS\Libraries\ZendeskApi.Client\Extensions\HttpResponseExtensions.cs:line 45 在 ZendeskApi.Client.Resources.AttachmentsResource.UploadAsync（字符串 文件名、流输入流、字符串令牌、CancellationToken 取消令牌）在 C:\www\TMS\Libraries\ZendeskApi.Client\Resources\AttachmentsResource.cs:line 44 在 Tms.ZendeskCore.Services.ZendeskManageFileService.UploadFileAsync（字符串 文件名，流流）在 C:\www\TMS\Libraries\Tms.ZendeskCore\Services\ZendeskManageFileService.cs:line 24 在 Tms.WebApi.Controllers.Support.ManageFileApiController.Upload() 在 C:\www\TMS\Web\Tms.WebApi\Controllers\Support\ManageFileApiController.cs:line 86 在 Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.TaskOfIActionResultExecutor.Execute（IActionResultTypeMapper 映射器，ObjectMethodExecutor 执行器，对象控制器，Object[] 论据）在 Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__Logged|12_1(ControllerActionInvoker 调用者）在 Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__Awaited|10_0(ControllerActionInvoker 调用者，任务 lastTask，下一个状态，作用域范围，对象状态，布尔值 已完成）在 Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow（ActionExecutedContextSealed 上下文）在 Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next（状态& next, Scope& 范围, Object& 状态, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__Awaited|13_0(ControllerActionInvoker 调用者，任务 lastTask，下一个状态，作用域范围，对象状态，布尔值 已完成）在 Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|19_0(ResourceInvoker 调用者，任务 lastTask，下一个状态，作用域范围，对象状态，布尔值 已完成）在 Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Logged|17_1(ResourceInvoker 调用者）在 Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0（端点 端点，任务 requestTask，ILogger 记录器）在 Microsoft.AspNetCore.Builder.Extensions.MapWhenMiddleware.Invoke(HttpContext 上下文）在 Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext 上下文）在 Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext 上下文）在 Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext 上下文）

标题 ======= Accept: / Accept-Encoding: gzip, deflate, br Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...7KlZaAycWieBAvkk2WUuTkI_UqNu9IzUhk0JAeLQkvU 缓存控制：无缓存连接：保持活动内容长度：114796 内容类型：multipart/form-data； 边界=--------------271301571241092277677258 主机： 本地主机：44373 用户代理：PostmanRuntime/7.28.3 邮递员令牌： 4fd12960-9bae-45f5-8ae1-e4a5080b887b

Answer 1

inputStream.CopyTo(stream) 同步复制流。您需要使用 StreamContent 而不是 ByteArrayContent，或者异步复制流 (CopyToAsync)。