Question

在我的WCF服务中，我收到405 method not allowed错误，然后发现了一条帖子，建议在我的WCF主机的Application_BeginRequest中包含以下内容：

protected void Application_BeginRequest(object sender, EventArgs e)
{
    if (HttpContext.Current.Request.HttpMethod == "OPTIONS")
    {
        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Headers",
                    "Accept, Content-Type,customHeader");

        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Methods",
                    "POST,GET,OPTIONS");

        HttpContext.Current.Response.AddHeader("Access-Control-Max-Age",
                    "172800");

        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Credentials",
                    "true");

        HttpContext.Current.Response.AddHeader("Access-Control-Expose-Headers",
                    "customHeader");

        HttpContext.Current.Response.AddHeader("Content-type",
                    "application/json");

        HttpContext.Current.Response.End();
    }
    else
    {
        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Headers",
                    "Accept, Content-Type,customHeader");

        HttpContext.Current.Response.AddHeader("Access-Control-Expose-Headers",
                    "customHeader");

        HttpContext.Current.Response.AddHeader("Content-type",
                    "application/json");
    }
}

但我正在使用控制台应用程序托管我的服务。

using (ServiceHost sc = new ServiceHost(typeof(DataRetriever)))
{
    sc.Open();

    foreach (var endPoints in sc.Description.Endpoints)
    {
        Console.WriteLine(endPoints.Address);
    }

    Console.ReadKey();
    sc.Close();
}

那么如何在控制台应用程序中包含标题。

Answer 1

在WCF中，可以通过类OperationContext的实例访问标头，可以通过OperationContext.Current（如果可用）访问它。

解决此问题的天真方法是在服务方法中使用此属性：

[ServiceContract]
public interface IMyService
{
    [OperationContract]
    void MyMethod();
}

internal class MyService: IMyService
{
    public void MyMethod()
    {
        Console.WriteLine("My Method");
        OperationContext.Current.OutgoingMessageHeaders.Add(MessageHeader.CreateHeader("headerFromMethod", "namespace", "headerFromMethodValue"));
    }
}

为完整起见，用于在控制台应用程序中托管此服务的代码（无需配置）为：

using (var serviceHost = new ServiceHost(typeof(MyService)))
{
    var endpoint = serviceHost.AddServiceEndpoint(typeof(IMyService), new BasicHttpBinding(), "http://localhost:9000");

    serviceHost.Open();

    Console.WriteLine("Open for business");
    Console.ReadLine();

    serviceHost.Close();
}

.NET客户端可以像这样访问标题：

var channel = ChannelFactory<IMyService>.CreateChannel(new BasicHttpBinding(), new EndpointAddress("http://localhost:9000"));

var contextChannel = channel as IContextChannel;
using (new OperationContextScope(contextChannel))
{
    channel.MyMethod();

    var incommingHeaders = OperationContext.Current.IncomingMessageHeaders;
    var header = incommingHeaders.GetHeader<string>("headerFromMethod", "namespace");
    Console.WriteLine("Header from server: " + header);
}

如果您有Fiddler，您还可以使用此工具查看标题。

虽然这种方法可以达到你想要的效果，但是你是否想要混合你的业务逻辑（包含在IMyService的实现中）和控制＆＃34;带外＆的逻辑是值得怀疑的。＃34;信息附带的信息。

通过实施IDispatchMessageInspector获得更清晰的分离，它允许您拦截服务器上的呼叫并在消息进出时修改消息：

public class ServerInterceptor: IDispatchMessageInspector, IEndpointBehavior
{
    object IDispatchMessageInspector.AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
    {
        return null;
    }

    void IDispatchMessageInspector.BeforeSendReply(ref Message reply, object correlationState)
    {
        reply.Headers.Add(MessageHeader.CreateHeader("header", "namespace", "headervalue"));
    }

    void IEndpointBehavior.ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
    {
        endpointDispatcher.DispatchRuntime.MessageInspectors.Add(this);
    }

    void IEndpointBehavior.Validate(ServiceEndpoint endpoint){}

    void IEndpointBehavior.AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters){}

    void IEndpointBehavior.ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime){}
}

以与以前相同的方式从.NET客户端访问标头。值得注意的是，您可以将AfterReceiveRequest方法中的信息传递给BeforeSendReply，因为前一种方法中返回的对象将作为correlationState参数传递给后者。如果您返回的标头取决于传入邮件的标头，这将非常有用 - 正如您的示例所示。

最后，要在服务上安装此功能，您需要修改托管代码，如下所示：

...
var endpoint = serviceHost.AddServiceEndpoint(typeof(IMyService), new BasicHttpBinding(), "http://localhost:9000");
endpoint.Behaviors.Add(new ServerInterceptor());
serviceHost.Open();
...

我们可以通过ServerInterceptor实现IEndpointBehavior

这一事实来做

Answer 2

这可以做到。您需要在主机（控制台）exe和Web服务类之间运行的共享变量。在调用WebService.Open（）之后，您必须运行一个连续循环，检查此共享变量是否有输入。代码看起来像这样：

//this would be your console host class
public class HostInterface
{
    string sHeaderString;
    public static string HeaderString {
        get { return sHeaderString; }
        set { sHeaderString += value; }


   public void main()
   {
      //code to start the web service
      System.ServiceModel.ServiceHost myWebService = default(System.ServiceModel.ServiceHost);

      //configure myWebService stuff
      myWebService.open();

      // here loop every second until the communication is stopped
      //check for new text in the shared sHeaderString 
      //written to by your web service class
      while (true) {
        if (myWebService.state != Communicationsstate.Opened){
            break; 
        }
        //write message out through console
        console.writeline("Headers:" + sHeaderString);
        Threading.Thread.Sleep(1000);
        //sleep 1 second before going trying next
      }
    }
  }
}

这将在您的Web服务的主类中，从您的控制台引用和更新“HeaderString”共享变量。

public void WriteHeadersToSharedVariable()
{
        //here, setting the headers into the shared variable instanced back on the console program
        HostInterface.Headerstring = GetHeadersFromRequest();
}

public string GetHeadersFromRequest()
{
    //some code to get the headers from inbound request
    return "blah blah blah";
}

希望你觉得这很有用。祝好运。

如何在控制台服务主机中包含WCF自定义标头

2 个答案: