{
  "response":{
    "code":200,
    "msg":"Remote service error",
    "result":""
  }
}

using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;

public class WebApiResultMiddleware : ActionFilterAttribute
{
  public override void OnResultExecuting(ResultExecutingContext context)
  {
    //根据实际需求进行具体实现
    if (context.Result is ObjectResult)
    {
      var objectResult = context.Result as ObjectResult;
      if (objectResult.Value == null)
      {
        context.Result = new ObjectResult(new { code = 404, sub_msg = "未找到资源", msg = "" });
      }
      else
      {
        context.Result = new ObjectResult(new { code = 200, msg = "", result = objectResult.Value });
      }
    }
    else if (context.Result is EmptyResult)
    {
      context.Result = new ObjectResult(new { code = 404, sub_msg = "未找到资源", msg = "" });
    }
    else if (context.Result is ContentResult)
    {
      context.Result = new ObjectResult(new { code = 200, msg = "", result= (context.Result as ContentResult).Content });
    }
    else if (context.Result is StatusCodeResult)
    {
      context.Result = new ObjectResult(new { code = (context.Result as StatusCodeResult).StatusCode, sub_msg = "", msg = "" });
    }
  }
}

public void ConfigureServices(IServiceCollection services)
{
  services.AddMvc(options =>
  {
    options.Filters.Add(typeof(WebApiResultMiddleware));
    options.RespectBrowserAcceptHeader = true;
  });
}