MVC的Web API：为预检响应具有无效的HTTP状态码404级

Question

我在两个服务器节点的服务时，我使用它有时它工作得很好，有时会错误

XMLHttpRequest cannot load.. Response for preflight has invalid HTTP status code 404 

我也跟着上计算器的答案，写了这个代码但它并没有解决问题

protected void Application_BeginRequest() 
    { 
     if (Request.HttpMethod == "OPTIONS") 
     { 
      Response.Flush(); 
     } 
    } 

的Web.config

<system.webServer> 
    <httpProtocol> 
     <customHeaders> 
     <remove name="X-Powered-By" /> 
     <add name="Access-Control-Allow-Origin" value="*" /> 
     <add name="Access-Control-Allow-Headers" value="Accept, Content-Type, Origin" /> 
     <add name="Access-Control-Allow-Methods" value="GET, PUT, POST, DELETE, OPTIONS" /> 
     </customHeaders> 
    </httpProtocol> 
    <security> 
     <requestFiltering> 
     <requestLimits maxAllowedContentLength="1073741824" /> 
     </requestFiltering> 
    </security> 
    <modules> 
     <remove name="FormsAuthentication" /> 
    </modules> 
    <handlers> 
     <remove name="ExtensionlessUrlHandler-Integrated-4.0" /> 
     <remove name="OPTIONSVerbHandler" /> 
     <remove name="TRACEVerbHandler" /> 
     <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" /> 
    </handlers> 
    </system.webServer> 

Answer 1

您可能需要使用此装饰[WebInvoke(Method = "OPTIONS", UriTemplate = "*")]一个经营合同，例如：

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

和操作实现将是：

public void GetOptions() 
    { 
     WebOperationContext.Current.OutgoingResponse.Headers.Add("Access-Control-Allow-Origin", "*"); 
     WebOperationContext.Current.OutgoingResponse.Headers.Add("Access-Control-Allow-Methods", "POST, GET, OPTIONS"); 
     WebOperationContext.Current.OutgoingResponse.Headers.Add("Access-Control-Allow-Headers", "Content-Type"); 
    }