返回网页API的自定义错误对象(Return custom error objects in Web

我有一个Web API，我正在使用MVC 4的Web API框架。如果有一个例外，我目前抛出一个新的HttpResponseException。即：

if (!Int32.TryParse(id, out userId))
    throw new HttpResponseException(Request.CreateErrorResponse(HttpStatusCode.BadRequest, "Invalid id"));

这将返回一个目的是在客户端是简单地{"message":"Invalid id"}

我想通过返回一个更详细的对象在这一反应获得更多的控制异常。就像是

{
 "status":-1,
 "substatus":3,
 "message":"Could not find user"
 }

我将如何去这样做呢？是连载我的错误对象，并设置它在响应消息的最佳方式？

我也进去看了ModelStateDictionary了一下，想出了这个有点“黑客”，但它仍然不是一个干净的输出：

var msd = new ModelStateDictionary();
msd.AddModelError("status", "-1");
msd.AddModelError("substatus", "3");
msd.AddModelError("message", "invalid stuff");
throw new HttpResponseException(Request.CreateErrorResponse(HttpStatusCode.BadRequest, msd));

编辑
看起来像一个自定义HttpError正是我需要的。这似乎这样的伎俩，现在让它从我的业务层扩展...

var error = new HttpError("invalid stuff") {{"status", -1}, {"substatus", 3}};
throw new HttpResponseException(Request.CreateErrorResponse(HttpStatusCode.BadRequest, error));

Answer 1:

这些答案的方式复杂得多，他们需要。

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        config.Filters.Add(new HandleApiExceptionAttribute());
        // ...
    }
}

public class HandleApiExceptionAttribute : ExceptionFilterAttribute
{
    public override void OnException(HttpActionExecutedContext context)
    {
        var request = context.ActionContext.Request;

        var response = new
        {
             //Properties go here...
        };

        context.Response = request.CreateResponse(HttpStatusCode.BadRequest, response);
    }
}

这就是你需要的。这也是好的，易于进行单元测试：

[Test]
public async void OnException_ShouldBuildProperErrorResponse()
{
    var expected = new 
    {
         //Properties go here...
    };

    //Setup
    var target = new HandleApiExceptionAttribute()

    var contextMock = BuildContextMock();

    //Act
    target.OnException(contextMock);

    dynamic actual = await contextMock.Response.Content.ReadAsAsync<ExpandoObject>();

    Assert.AreEqual(expected.Aproperty, actual.Aproperty);
}

private HttpActionExecutedContext BuildContextMock()
{
    var requestMock = new HttpRequestMessage();
    requestMock.Properties.Add(HttpPropertyKeys.HttpConfigurationKey, new HttpConfiguration());

    return new HttpActionExecutedContext()
    {
        ActionContext = new HttpActionContext
        {
            ControllerContext = new HttpControllerContext
            {
                Request = requestMock
            }

        },
        Exception = new Exception()
    };
}

Answer 2:

我认为这将这样的伎俩：

创建业务层的自定义异常类：

 public class MyException: Exception
 {
    public ResponseStatus Status { get; private set; }
    public ResponseSubStatus SubStatus { get; private set; }
    public new string Message { get; private set; }

    public MyException()
    {}

    public MyException(ResponseStatus status, ResponseSubStatus subStatus, string message)
    {
        Status = status;
        SubStatus = subStatus;
        Message = message;
    }
 }

创建一个静态方法来生成HttpError从实例MyException 。我使用的是反射在这里，所以我可以添加属性MyException ，总是让他们回到W / O更新Create ：

    public static HttpError Create<T>(MyException exception) where T:Exception
    {
        var properties = exception.GetType().GetProperties(BindingFlags.Instance 
                                                         | BindingFlags.Public 
                                                         | BindingFlags.DeclaredOnly);
        var error = new HttpError();
        foreach (var propertyInfo in properties)
        {
            error.Add(propertyInfo.Name, propertyInfo.GetValue(exception, null));
        }
        return error;
    }

我现在有一个一般的异常处理程序自定义属性。类型的所有异常MyException将在这里进行处理：

public class ExceptionHandlingAttribute : ExceptionFilterAttribute
{
    public override void OnException(HttpActionExecutedContext context)
    {
        var statusCode = HttpStatusCode.InternalServerError;

        if (context.Exception is MyException)
        {
            statusCode = HttpStatusCode.BadRequest;
            throw new HttpResponseException(context.Request.CreateErrorResponse(statusCode, HttpErrorHelper.Create(context.Exception)));
        }

        if (context.Exception is AuthenticationException)
            statusCode = HttpStatusCode.Forbidden;

        throw new HttpResponseException(context.Request.CreateErrorResponse(statusCode, context.Exception.Message));
    }
}

因为我觉得在这个计划中洞，我会玩这个多一点和更新。