我有一个Web API我正在使用MVC 4 Web API框架。如果有一个异常，我目前抛出一个新的HttpResposneException。即：
if (!Int32.TryParse(id,out userId))
throw new HttpResponseException(Request.CreateErrorResponse(HttpStatusCode.BadRequest,"Invalid id"));
这会向客户端返回一个对象，即{“message”：“无效的ID”}
我想通过返回一个更详细的对象来进一步控制对异常的响应。就像是
{
"status":-1,"substatus":3,"message":"Could not find user"
}
我怎么会这样做？是序列化我的错误对象和设置它在响应消息中的最佳方式吗？
我也看了ModelStateDictionary一点，并提出了这一点“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的HttpError是我需要的。这似乎做的伎俩，现在使它可以从我的业务层扩展…
var error = new HttpError("invalid stuff") {{"status",-1},{"substatus",3}};
throw new HttpResponseException(Request.CreateErrorResponse(HttpStatusCode.BadRequest,error));
解决方法
这些答案比他们需要的更复杂。
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。它也很好，容易的单元测试：
[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()
};
}
