服务器高负载大请求体时随机出现The client has disconnected错误

我们的ASP.NET Core服务器在高流量场景下，仅针对请求体较大的请求会随机抛出以下错误，且尝试过分块读取请求体后问题仍未解决：

Microsoft.AspNetCore.Connections.ConnectionResetException: The client has disconnected
System.Runtime.InteropServices.COMException: The specified network name is no longer available. (0x80070040)

--- End of inner exception stack trace ---
at Microsoft.AspNetCore.Server.IIS.Core.IO.AsyncIOOperation.GetResult(Int16 token)
at Microsoft.AspNetCore.Server.IIS.Core.IISHttpContext.ReadBody()
at System.IO.Pipelines.PipeCompletion.ThrowLatchedException()
at System.IO.Pipelines.Pipe.GetReadResult(ReadResult& result)
at System.IO.Pipelines.Pipe.ReadAsync(CancellationToken token)
at System.IO.Pipelines.Pipe.DefaultPipeReader.ReadAsync(CancellationToken cancellationToken)
at Microsoft.AspNetCore.Server.IIS.Core.IISHttpContext.ReadAsync(Memory1 memory, CancellationToken cancellationToken) at Microsoft.AspNetCore.Server.IIS.Core.HttpRequestStream.ReadAsyncInternal(Memory1 buffer, CancellationToken cancellationToken)
at Microsoft.AspNetCore.WebUtilities.FileBufferingReadStream.ReadAsync(Memory`1 buffer, CancellationToken cancellationToken)
at System.Text.Json.JsonSerializer.ReadAsync[TValue](Stream utf8Json, Type returnType, JsonSerializerOptions options, CancellationToken cancellationToken)
at Microsoft.AspNetCore.Mvc.Formatters.SystemTextJsonInputFormatter.ReadRequestBodyAsync(InputFormatterContext context, Encoding encoding)
at Microsoft.AspNetCore.Mvc.Formatters.SystemTextJsonInputFormatter.ReadRequestBodyAsync(InputFormatterContext context, Encoding encoding)
at Microsoft.AspNetCore.Mvc.ModelBinding.Binders.BodyModelBinder.BindModelAsync(ModelBindingContext bindingContext)
at Microsoft.AspNetCore.Mvc.ModelBinding.ParameterBinder.BindModelAsync(ActionContext actionContext, IModelBinder modelBinder, IValueProvider valueProvider, ParameterDescriptor parameter, ModelMetadata metadata, Object value, Object container)
at Microsoft.AspNetCore.Mvc.Controllers.ControllerBinderDelegateProvider.<>c__DisplayClass0_0.<g__Bind|0>d.MoveNext()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__Awaited|13_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
at Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.g__Awaited|6_0(ExceptionHandlerMiddleware middleware, HttpContext context, Task task)

错误根源分析 #

错误代码0x80070040对应网络连接中断，结合大请求体+高流量场景，问题根源通常不在请求体读取方式，而是IIS/Kestrel的请求限制、超时配置，或前端/反向代理的连接超时导致请求未传输完成就被断开。

解决方案 #

1. 调整IIS请求与应用池配置 #

• 请求筛选设置：打开IIS管理器→目标站点→请求筛选→编辑功能设置，增大最大允许内容长度（建议设为1GB即1073741824字节），勾选允许未列出的文件扩展名（若请求体为自定义格式）。
• 应用池优化：进入应用池→高级设置，将队列长度从默认1000调至2000；进程模型→闲置超时设为0，避免高流量时进程被回收。

2. 优化ASP.NET Core全局配置 #

• 在appsettings.json中添加Kestrel限制配置：

  "Kestrel": {
    "Limits": {
      "MaxRequestBodySize": 1073741824,
      "RequestHeadersTimeout": "00:02:00"
    }
  }
  

• 在Program.cs中全局设置请求体大小：

  // .NET 6+ 示例
  var builder = WebApplication.CreateBuilder(args);
  // 注册服务...
  var app = builder.Build();
  
  app.UseHttpsRedirection();
  // 全局覆盖请求体大小限制
  app.Use(async (context, next) =>
  {
      var maxSizeFeature = context.Features.Get<IHttpMaxRequestBodySizeFeature>();
      if (maxSizeFeature != null)
      {
          maxSizeFeature.MaxRequestBodySize = 1073741824;
      }
      await next();
  });
  app.UseAuthorization();
  app.MapControllers();
  app.Run();
  

3. 检查反向代理/负载均衡超时设置 #

如果使用Nginx、Apache或CDN等代理服务：

• Nginx：在server块中添加client_max_body_size 1g;，调整proxy_connect_timeout 120s;和proxy_read_timeout 120s;。
• Apache：设置LimitRequestBody 1073741824，调整ProxyTimeout 120。
• 确保CDN/负载均衡未设置过短的连接超时，避免大请求传输中途被断开。

4. 全局捕获异常并优雅处理 #

在全局异常中间件中捕获该类异常，避免日志泛滥并返回友好提示：

app.UseExceptionHandler(errorApp =>
{
    errorApp.Run(async context =>
    {
        var exceptionFeature = context.Features.Get<IExceptionHandlerPathFeature>();
        var ex = exceptionFeature?.Error;
        
        if (ex is ConnectionResetException || 
            (ex?.InnerException is COMException comEx && comEx.HResult == -2147024832)) // 对应0x80070040的HResult
        {
            context.Response.StatusCode = StatusCodes.Status499ClientClosedRequest;
            await context.Response.WriteAsync("请求连接中断，请稍后重试");
        }
        else
        {
            context.Response.StatusCode = StatusCodes.Status500InternalServerError;
            await context.Response.WriteAsync("服务器内部错误");
        }
    });
});

5. 调整TCP/IP网络配置 #

• 打开注册表HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters：
  • 设置TcpTimedWaitDelay为30（十进制，缩短TIME_WAIT状态时长）。
  • 设置MaxUserPort为65534（十进制，增大可用端口范围）。
• 检查服务器防火墙规则，排除针对大流量长连接的误拦截。

内容的提问来源于stack exchange，提问作者Abhijit Mutyal