ASP.NET 异常时Core HttpContext.Response.StatusCode为200

Question

我有一个抛出异常的端点。

[ApiController]
[Route("api")]
public class LegacyController : ControllerBase
{
    [HttpPost("endpoint")]
    public async Task<ActionResult<IEnumerable<Entitty>>> GetAll()
    {
        throw new Exception();
        return Ok(t.ToList());
    }
}

我有自定义 Http 日志过滤器，看起来像这样

using Microsoft.AspNetCore.Http;

namespace Client.API.Extensions
{
    public class HttpLoggingMiddleware
    {
        private readonly RequestDelegate _next;
        private readonly ILogger _logger;

        public HttpLoggingMiddleware(RequestDelegate next, ILogger<HttpLoggingMiddleware> logger)
        {
            _next = next;
            _logger = logger;
        }

        public async Task Invoke(HttpContext context)
        {
            try
            {
                await _next(context);
            }
            finally
            {
                _logger.LogInformation(
                    "Request {method} {url} => {statusCode}",
                    context.Request?.Method,
                    context.Request?.Path.Value,
                    context.Response?.StatusCode);
            }
        }
    }
}

当我调用此端点时，context.Response?.StatusCode 为 200。为什么？

然而，Postman 告诉我我的请求失败了，我看到了错误本身，因此一切看起来都很正常。 尽管日志包含 200 条状态代码消息，而不是 500。

编辑：这是我的启动（一些部分被删除）。

namespace Client.API
{
    public class Startup
    {
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            ...
            app.UseHttpsRedirection();

            app.UsePathBase(new PathString(basePath));
            app.UseRouting();

            app.UseMiddleware<HttpLoggingMiddleware>();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
            endpoints.MapControllers();
            });
        }
    }
}

Answer 1

如果你想捕获异常，你需要使用特定的中间件app.UseExceptionHandler(); ，所以首先我使用这个中间件来设置日志。

代码是：

app.UseExceptionHandler(
  appErr =>
  {
    appErr.Run(
    async context =>
    {
      logger.LogInformation(
      "Request {method} {url} => {statusCode}",
       context.Request?.Method,
       context.Request?.Path.Value,
       context.Response?.StatusCode);
    });
});

但是有一个问题，这个中间件只能捕获异常，所以当响应码不是500时，请求不会进入这个中间件。

最后我换了一个方法，我用try/catch来捕获异常，自己设置StatusCode就成功了。 代码如下：

public class HttpLoggingMiddleware
    {
        private readonly RequestDelegate _next;
        private readonly ILogger<HttpLoggingMiddleware> _logger;

        public HttpLoggingMiddleware(RequestDelegate next,ILogger<HttpLoggingMiddleware> logger)
        {
            _next = next;
            _logger = logger;
        }

        public async Task Invoke(HttpContext context)
        {
            try
            {
                await _next(context);
            }
            catch (Exception)
            {
                //catch the Exception and set the StatusCode 
                context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
            }
            finally
            {
                _logger.LogInformation(
                    "Request {method} {url} => {statusCode}",
                    context.Request?.Method,
                    context.Request?.Path.Value,
                    context.Response?.StatusCode);
            }
        }

    }