Web API Controller中的异常处理和抛出自定义错误消息

Question

对于我的一个项目,我使用的是带有SOA架构的Web API.在Controller中,我希望捕获异常(由Repository抛出)并返回HttpResposeMessage.

我想要的是应该有一个继承ApiController(class BaseController : ApiController)的BaseController ,我的每个Controller应该由baseController继承,
例如class TaskController : BaseController,如果我的控制器中发生任何异常,那么应该由它来处理BaseController.演示:

以下是VS解决方案中的项目:(项目结构)

XYZ.Model
XYZ.Repository
XYZ.WebServices
XYZ.Exception
XYZ.UI

代码:XYZ.Model

public class Error
{
    public string Code { get; set; }
    public string Message { get; set; }

}

XYZ.Exception

// To create the custom exception as per our need
public class BaseException : Exception
{
    private Error _error;
    public Error Error
    {
        get { return _error; }
    }

    public BaseException()
    {
        _error = new Error();
    }

    public void SetErrorCode(string code)
    {
        _error.Code = code;
    }

    public void SetErrorMessage(string message)
    {
        _error.Message = message;
    }
}


public class TaskNotFoundException : BaseException
{
    public TaskNotFoundException()
    {
        string errorCode = "T0001";
        base.SetErrorCode(errorCode);
        base.SetErrorMessage((new ExceptionMessage()).GetExceptionMessage(errorCode));
    }
}

XYZ.Repository

public Task UpdateTaskDetails(Task task)
{
    try
    {
        //--Task updating logic--//
    }
    catch (Exception ex)
    {
        throw new TaskUpdateFailedException();
    }
    return task;
}

XYZ.WebServices

public class BaseController : ApiController
{
    public HttpResponseMessage CreateResponseMessage()
    {
        try
        {
            GetTasksByUserIdAndProjectId(new TaskQuery());
        }
        catch(BaseException exception)
        {
            return Request.CreateResponse(HttpStatusCode.InternalServerError, exception.Error);
        }
    }

    public virtual  List<Task> GetTasksByUserIdAndProjectId(TaskQuery query)
    {
        Console.WriteLine("I can be overridden");
    }
}


public class TaskController : BaseController
{
    [HttpPost]
    public override List<Task> GetTasksByUserIdAndProjectId(TaskQuery query)
    {
        return _taskRepo.GetTasksByUserIdAndProjectId(query.UserId, query.ProjectId);
    }

}

在TaskController如果任何异常发生GetTasksByUserIdAndProjectId的方法应该抛出异常的BaseController CreateReponseMessage(),有它会返回HttpResponseMessage给客户端.

注意:在每个Controller中都有多个Get/Put/Post方法,因此无法声明所有方法(Web服务方法)BaseController以捕获项目当前结构中子类的异常.

有没有更好的方法来处理Web API中的Exception,它很容易适应我的项目？

Answer 1

我们使用这样的异常过滤器:

首先我们创建自己的异常:

public class UserFriendlyException: Exception
    {
        public UserFriendlyException(string message) : base(message) { }
        public UserFriendlyException(string message, Exception innerException) : base(message, innerException) { }
    }

然后我们创建一个过滤器:

public class UserFriendlyExceptionFilterAttribute: ExceptionFilterAttribute
    {
        public override void OnException(HttpActionExecutedContext context)
        {
            var friendlyException = context.Exception as UserFriendlyException;
            if (friendlyException != null)
            {
                context.Response = context.Request.CreateResponse(HttpStatusCode.BadRequest, new {Message = friendlyException.Message}); 
            }
        }
    }

最后在WebApi的配置中添加了该过滤器.

public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            ...


            config.Filters.Add(new UserFriendlyExceptionFilterAttribute());

            ...
        }
    }

使用此解决方案,您可以在代码中的任何位置抛出UserFriendlyException,响应将根据过滤器.