Question

我编写了自定义ServiceRunner并重写了HandleException方法。我可以看到，如果服务中存在未处理的异常，HandleException方法返回的对象将成为服务响应。我希望返回服务在成功时返回的相同responseDTO类型。我有没有办法在HandleException中访问，遇到异常的服务的responseDTO类型？

编辑：根据收到的答复，我实现了服务（在F＃中），其DTO /服务类型定义如下：

type CS()=
    interface IReturn<Op<list<Y>,list<E>>>
    member val key = List<int>() with get,set

type CSService() = 
    interface IService
    member this.Get(request: CS)=
        //service code here returning Op<list<Y>,seq<E>> type

因此，我期望在HandleException中收到的类型是Op<list<Y>,list<E>> （Y和E是在bin文件夹中可用的dll中定义的已知类型）

根据建议我尝试了以下两个选项，因为WebRequestUtils在两个命名空间中都可用：

Type test1 = ServiceStack.WebRequestUtils.GetErrorResponseDtoType(request.GetType());//error
        Type test2 = ServiceStack.ServiceClient.Web.WebRequestUtils.GetErrorResponseDtoType(request.GetType());

对于test1，我收到以下异常：

Could not load type 'ServiceStack.ErrorResponse' from assembly 'ServiceStack.Interfaces, Version=3.9.71.0, Culture=neutral, PublicKeyToken=null'.

堆栈追踪：

at ServiceStack.WebRequestUtils.GetErrorResponseDtoType(Type requestType)
at M.ServiceStackWebAPP.MyCustomServiceRunner`1.HandleException(IRequestContext requestContext, TRequest request, Exception ex) in d:\Projects\ServiceStack\M.WebService\MyCustomServiceRunner.cs:line 167
at ServiceStack.ServiceHost.ServiceRunner`1.Execute(IRequestContext requestContext, Object instance, TRequest request)
at ServiceStack.ServiceHost.ServiceRunner`1.Process(IRequestContext requestContext, Object instance, Object request)
at ServiceStack.ServiceHost.NServiceExec`1.Execute(IRequestContext requestContext, Object instance, Object request, String requestName)
at ServiceStack.ServiceHost.NServiceRequestExec`2.Execute(IRequestContext requestContext, Object instance, Object request)
at ServiceStack.ServiceHost.ServiceController.<>c__DisplayClass15.<>c__DisplayClass17.<RegisterNServiceExecutor>b__14(IRequestContext reqCtx, Object req)
at ServiceStack.ServiceHost.ServiceController.ManagedServiceExec(ServiceExecFn serviceExec, Object service, IRequestContext requestContext, Object dto)
at ServiceStack.ServiceHost.ServiceController.<>c__DisplayClass15.<RegisterNServiceExecutor>b__13(IRequestContext requestContext, Object dto)
at ServiceStack.ServiceHost.ServiceController.Execute(Object request, IRequestContext requestContext)
at ServiceStack.WebHost.Endpoints.EndpointHost.ExecuteService(Object request, EndpointAttributes endpointAttributes, IHttpRequest httpReq, IHttpResponse httpRes)
at ServiceStack.WebHost.Endpoints.Support.EndpointHandlerBase.ExecuteService(Object request, EndpointAttributes endpointAttributes, IHttpRequest httpReq, IHttpResponse httpRes)
at ServiceStack.WebHost.Endpoints.RestHandler.GetResponse(IHttpRequest httpReq, IHttpResponse httpRes, Object request)
at ServiceStack.WebHost.Endpoints.RestHandler.ProcessRequest(IHttpRequest httpReq, IHttpResponse httpRes, String operationName)

对test2的调用成功，但我收到ErrorResponse类型作为返回值而不是预期的Op<list<Y>,list<E>>。

我还缺少什么吗？

Answer 1

由于ServiceStack Services允许您返回任何响应类型，如果未发生异常，最终无法确切知道服务将返回什么，因为这将依赖于运行时执行的服务实现逻辑抛出异常后，例如：

public object Any(Request request)
{
    throw new Exception(); //No way of knowing what Service would've returned

    if (SomeCustomLogic(request))
        return new Response1();

    return new Response2();
}

虽然您遵循ServiceStack建议使用返回类型标记您的请求DTO，例如：

public class MyRequest : IReturn<MyResponse> { ... }

或ServiceStack的约定，即以请求DTO命名的响应DTO，后缀为Response，例如：

public class GetCustomers { ... } 
public class GetCustomersResponse { ... }

然后您可以使用WebRequestUtils.GetErrorResponseDtoType(requestType)从请求DTO类型中检索响应类型，例如：

public override object HandleException(IRequest request, T requestDto, Exception ex)
{
    var responseType = WebRequestUtils.GetErrorResponseDtoType(requestDto.GetType());
}

如果ServiceStack无法推断响应类型（即不使用上面推荐的约定），则返回通用ErrorResponse类型。

另请注意，您可以使用更有用的DtoUtils.CreateErrorResponse()来返回填充错误Response DTO，该错误具有响应DTO的ResponseStatus属性，例如：

public override object HandleException(IRequest request, T requestDto, Exception ex)
{
    var errorResponse = DtoUtils.CreateErrorResponse(requestDto, ex);
}

在ServiceStack中的自定义ServiceRunner的HandleException中访问responseDTO类型

1 个答案: