WCF禁止在JSON响应中返回__type [英] WCF suppress returning __type in JSON response

问题描述

抱歉，这有点长，但是我相信所有信息都是必需的:

Sorry this is a little long, but all the information is needed I beleive:

具有内置JSON.NET的
• .NET 4.5
• 我定义了以下行为:

• .NET 4.5 with built in JSON.NET
• I have the following behaviours defined:

Viz:

<behaviors>
    <endpointBehaviors>
        <behavior name="WebBehavior">
            <webHttp helpEnabled="true" automaticFormatSelectionEnabled="true" />
        </behavior>
    </endpointBehaviors>
    <serviceBehaviors>
        <behavior name="ServiceBehaviour">
            <serviceMetadata httpGetEnabled="true" httpGetBinding="" httpGetBindingConfiguration="" />
            <serviceDebug includeExceptionDetailInFaults="true" />
        </behavior>
    </serviceBehaviors>
</behaviors>

为我服务:

  [ServiceContract]
    public interface IWebServiceSrms
    {
        //-- Countries --------------------------------------------------------
        [OperationContract]
        [WebInvoke(Method = "GET", BodyStyle = WebMessageBodyStyle.Wrapped, UriTemplate = "/Countries")]
        [return: MessageParameter(Name = "Countries")]
        List<Country> Countries();

        [OperationContract]
        [WebInvoke(Method = "GET", BodyStyle = WebMessageBodyStyle.Wrapped, UriTemplate = "/Countries/{aId}")]
        [return: MessageParameter(Name = "Country")]
        Country Country(string aId);
        //-- /Countries -------------------------------------------------------
    }

我已经实现了IErrorHandler，然后实现了以下 ErrorResponse 以将JSON响应返回给客户端:

I have implemented an IErrorHandler and then the following ErrorResponse to return JSON responses to clients:

[DataContract(IsReference = false)]
public class ErrorResponse
{
    public ErrorResponse(ErrorTypes aErrorType, ErrorNumber aErrorNumber, string aMessage)
    {
        ApiErrorBase = new ApiErrorBase {ErrorNumber = aErrorNumber, ErrorType = aErrorType, Message = aMessage};
    }
    public ErrorResponse(IApiErrorBase aApiErrorBase)
    {
        ApiErrorBase = aApiErrorBase as ApiErrorBase;
    }
    [DataMember(Name = "ApiError")]
    public ApiErrorBase ApiErrorBase { get; set; }

和 IApiErrorBase 定义为:

public interface IApiErrorBase
{
    ErrorNumber ErrorNumber { get; set; }
    ErrorTypes ErrorType { get; set; }
    string Message { get; set; }
}

和一个具体的 ApiErrorNase 定义为:

[DataContract(IsReference = false)]
public class ApiErrorBase : IApiErrorBase
{
    [DataMember(Name = "ErrorType")]
    private string ErrType
    {
        get { return ErrorType.ToString(); }
        set { return; }
    }
    public ApiErrorBase()
    {
        ErrorNumber = ErrorNumber.ErrUnknown;
        ErrorType = ErrorTypes.UnknownError;
        Message = "";
    }
    [DataMember]
    public ErrorNumber ErrorNumber { get; set; }
    [IgnoreDataMember]
    public ErrorTypes ErrorType { get; set; }
    [DataMember]
    public string Message { get; set; }
}

然后我有一个辅助方法来引发异常，该异常最终将错误返回给客户端:

I then have a helper method to throw an exception which ultimately returns the error to the client:

public static class ErrorHelper
{
    public static void ReturnErrorToClient<T>(ErrorNumber aErrorNumber, ErrorTypes aErrorType, string aMessage, HttpStatusCode aHttpStatusCode = HttpStatusCode.BadRequest) where T : IApiErrorBase, new() 
    {
        T apiErrorBase = new T {ErrorNumber = aErrorNumber, ErrorType = aErrorType, Message = aMessage};

        ErrorResponse errorResponse = new ErrorResponse(apiErrorBase);

        throw new WebFaultException<ErrorResponse>(errorResponse, aHttpStatusCode);
    }
}

在我创建了以下 ApiErrorAnotherOne 后代类之前，这一切都按预期进行，并且效果良好:

This all works well and as expected until I created the following ApiErrorAnotherOne descendant class:

    [DataContract(IsReference = false)]
    [KnownType(typeof(ApiErrorAnotherOne))]
    public class ApiErrorAnotherOne : ApiErrorBase 
    {
        [DataMember]
        public string Homer { get; set; }

        public ApiErrorAnotherOne()
        {
            Homer = "You don't make friends with salad.";
        }
    }

第一个问题是当我收到以下错误时，我必须添加 [KnownType(typeof(ApiErrorAnotherOne))] :

The first issue was I had to add [KnownType(typeof(ApiErrorAnotherOne))] as I received the following error:

aError = {"Type 'WebService_SRMS.Errors.ApiErrorSomeOtherOne' with data contract name 'ApiErrorSomeOtherOne:http://schemas.datacontract.org/2004/07/WebService_SRMS.Errors' is not expected. Consider using a DataContractResolver or add any types not known statically to the list of kn...

但是现在我的JSON响应包括 __ type ，如下所示:

However now my JSON response includes __type as below:

{
    "ApiError": {
        "__type": "ApiErrorDono:#WebService_SRMS.Errors",
        "ErrorNumber": 1,
        "ErrorType": "UnknownError",
        "Message": "",
        "Homer": "You don't make friends with salad."
    }
}

所以我的问题是:

1. 为什么__type出现在响应中? (其余的响应是我想要的)
2. 如何从JSON响应中删除__type?

推荐答案

您需要指示服务实际返回的内容.有几种方法:

You need to instruct the service what actually it has to return. There are several ways:

在操作合同的WebGet属性中
• 设置ResponseFormat=WebMessageFormat.Json
在Web.config中的行为下，在webhttp设置中
• 指定defaultOutgoingResponseFormat="Json"

• setting ResponseFormat=WebMessageFormat.Json in your WebGet attribute of your operation contracts
• specifying defaultOutgoingResponseFormat="Json" in webhttp setting under behaviours in your web.config

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