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I have a ASP.NET Core 6 REST API application, installed on the on-premise server with IIS. In one of the environments, about 20% of queries fail due to an empty HttpContext.Response.Body object. I use Audit.NET for logging requests and responses. Audit.NET response log looks like this:

"Action": {
    "HttpMethod": "POST",
    "ResponseStatus": "OK",
    "ResponseStatusCode": 200,
    "ResponseBody": {
        "Type": "application/json; charset=utf-8",
        "Value": ""
    }
}

The problem is similar to this https://github.com/aws/aws-lambda-dotnet/issues/1457, but I don't use AWS.

I suspect that the problem may be caused by the use of Audit.Net, but analyzing the code of the added middleware, I cannot find the cause of the error.

Has anyone encountered such a problem?

I tried mass testing on local environments but failed to reproduce the reported issue.

EDIT 21.08.2023: My code looks like this:

Program.cs

var app = builder.Build();
app.Use((context, next) =>
        {
           context.Request.EnableBuffering();
           return next();
        });
app.UseExceptionHandler(GlobalExceptionHandler.Configure);
app.UseAuditMiddleware(_ => _
                            .FilterByRequest(r => r.Path.Value?.Contains("/api/") == true)
                            .WithEventType(context => context.Request.Path)
                            .IncludeRequestBody()
                            .IncludeResponseBody());
  
app.UseMiddleware<ExceptionHandlingMiddleware>();
app.UseSwagger();
app.MapControllers();

GlobalExceptionHandler.cs

internal class GlobalExceptionHandler
{
   public static void Configure(IApplicationBuilder applicationBuilder)
   {
      applicationBuilder.Run(async context =>
      {
         context.Response.StatusCode = StatusCodes.Status500InternalServerError;
         context.Response.ContentType = "application/json";
    
         var status = context.Features.Get<IStatusCodeReExecuteFeature>();
         var error = context.Features.Get<IExceptionHandlerFeature>();
         if (error != null)
         {
            var responseDetails = GetFullExceptionDetails(status, error.Error);
            await context.Response.WriteAsync(responseDetails, Encoding.UTF8);
         }
      });
   }
}

ExceptionHandlingMiddleware.cs


internal class ExceptionHandlingMiddleware
{
   public async Task InvokeAsync(HttpContext httpContext)
   {
      try
      {
         await _next(httpContext);
      }
      catch (Exception ex)
      {
         var errorResponse = HandleBusinessException(exception as MyException);
         var statusCode = GetStatusCode(exception as MyException);
 
         context.Response.StatusCode = statusCode;
         context.Response.ContentType = "application/json";
         await context.Response.WriteAsync(errorResponse.Serialize());
      }
   }
}
Pawel
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  • I suggest you could check the logs by enable the Information level for the logging. Besides, I suggest you could check the response body by adding the middleware before the Audit response. – Brando Zhang Aug 07 '23 at 10:54
  • Are you setting the `IncludeResponseBody` setting to true? Are you adding the middleware to the pipeline before the call to `.UseMvc()`? – thepirat000 Aug 10 '23 at 05:14
  • Above I pasted the code from my project. – Pawel Aug 21 '23 at 20:11
  • BTW `"application/json; charset=utf-8"` is redundant: don't specify `charset` for JSON because JSON requires UTF-8 anyway: [if it isn't UTF-8 then it isn't valid JSON](https://stackoverflow.com/questions/9254891/what-does-content-type-application-json-charset-utf-8-really-mean). – Dai Aug 21 '23 at 20:20

0 Answers0