Question

我使用托管在控制台应用程序上的CORS的WCF服务在.Net 4.5中运行良好。现在，该应用程序需要在.Net 3.5中运行，并且预检OPTIONS请求现在无法执行任何POST请求

以下是服务的界面：

    [OperationContract]
    [WebInvoke(Method = "POST", RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.WrappedRequest)]
    BiometricCaptureResponse Start(BiometricCaptureRequest biometricRequest);

    [OperationContract]
    [WebInvoke(Method = "OPTIONS", UriTemplate = "*")]
    void Options();

实际服务：

    public BiometricCaptureResponse Start(BiometricCaptureRequest biometricRequest)
    {
        //Stuff and things
    }

    public void Options()
    {
        return;
    }

应用于请求和响应的CORS行为

    public string clientOrigin;       

    public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
    {
        HttpRequestMessageProperty requestProperty = request.Properties[HttpRequestMessageProperty.Name]
                      as HttpRequestMessageProperty;

        if (requestProperty != null && requestProperty.Headers.AllKeys.Contains("Origin") && !string.IsNullOrEmpty(requestProperty.Headers["Origin"]))
        {
            clientOrigin = requestProperty.Headers["Origin"];
        }

        return null;
    }

    public void BeforeSendReply(ref Message reply, object correlationState)
    {
        HttpResponseMessageProperty httpHeader = reply.Properties["httpResponse"] as HttpResponseMessageProperty;

        if (httpHeader != null)
        {
            httpHeader.ApplyCrossOriginSupport(clientOrigin); 
        }
    }

    public static void ApplyCrossOriginSupport(this HttpResponseMessageProperty message, string origin)
    {
        message.Headers.Add("Access-Control-Allow-Origin", origin);
        message.Headers.Add("Access-Control-Allow-Method", ConfigurationManager.AppSettings["Access-Control-Allow-Method"]);
        message.Headers.Add("Access-Control-Allow-Headers", ConfigurationManager.AppSettings["Access-Control-Allow-Headers"]);
    }

这一切都在4.5中完成，这是将要发生的过程：

AfterReceiveRequest（）
选项（）服务点击
BeforeSendReply（）
AfterReceiveRequest（）
开始（）
BeforeSendReply（）

现在在3.5中，Ooptions服务不会被命中，这将导致整个请求失败，是否有任何我缺少的东西让这个工作在3.5？

我从Chrome控制台获取的错误是：

OPTIONS http://localhost:8502/testservice.svc/rest/Start net::ERR_CONNECTION_RESET

这可能与WebInvoke属性有关吗？它的MSDN页面将其描述为4.5 / 3.5客户端技术，而我只使用.Net 3.5。

更新：更改选项服务的以下属性以使用所有方法

    [WebInvoke(Method = "OPTIONS", UriTemplate = "*")]
    [WebInvoke(Method = "*", UriTemplate = "*")]

允许选项请求命中服务，应用程序可以像这样在功能上工作，但这仍然不是最佳解决方案，因为它不是特定于OPTIONS请求，这背后的任何原因？

Answer 1

我担心WebHttpDispatchOperationSelector的.Net 3.5版本中存在一个小错误。

选择器无法识别方法OPTIONS与* UriTemplate的组合。

作为一种解决方法，您可以使用自定义版本替换默认的WebHttpBehavior。

public class CorsWebHttpDispatchOperationSelector : WebHttpDispatchOperationSelector
{

    private WebHttpDispatchOperationSelector target;
    private ServiceEndpoint endpoint;

    OperationDescription optionOperation;

    public CorsWebHttpDispatchOperationSelector(ServiceEndpoint endpoint, WebHttpDispatchOperationSelector target)
    {
        this.target = target;
        this.endpoint = endpoint;

        foreach (var item in this.endpoint.Contract.Operations) {
            var webInvoke = item.Behaviors.OfType<WebInvokeAttribute>().FirstOrDefault();
            if (webInvoke != null && webInvoke.Method.Equals("options",StringComparison.OrdinalIgnoreCase) && webInvoke.UriTemplate == "*") {
                optionOperation = item;
                break;
            }
        }
    }
    #region IDispatchOperationSelector Members

    protected override string SelectOperation(ref Message message, out bool uriMatched)
    {
        var result = target.SelectOperation(ref message);

        var matched = message.Properties["UriMatched"] as bool?;
        message.Properties.Remove("UriMatched");
        message.Properties.Remove("HttpOperationName");
        uriMatched = matched.HasValue && matched.Value;

        var httpRequest = message.Properties["httpRequest"] as HttpRequestMessageProperty;

        var cond = string.IsNullOrEmpty(result) && 
                        httpRequest != null && 
                        httpRequest.Method.Equals("options",StringComparison.OrdinalIgnoreCase);

        if (cond && optionOperation != null) {
            result = optionOperation.Name;
            uriMatched = true;
        }

        return result;
    }
    #endregion
}

public class CorsWebHttpBehavior : WebHttpBehavior {
    protected override WebHttpDispatchOperationSelector GetOperationSelector(ServiceEndpoint endpoint)
    {
        return new CorsWebHttpDispatchOperationSelector(endpoint, base.GetOperationSelector(endpoint));
    }
}

将WCF CORS restful服务从.Net 4.5转换为3.5会导致预检请求中断

1 个答案: