WCF 发现客户端无法找到可单独访问的服务

Question

我正在尝试将临时发现添加到简单的 WCF 服务客户端设置（当前通过控制台应用程序中的自托管实现）。在 Windows 7 上使用 VS2010 进行调试，并执行我在在线教程中可以找到的任何操作，但发现客户端仍然什么也没找到。不用说，如果我打开客户端到正确的服务端点，我就可以从客户端访问该服务。

服务代码：

using (var selfHost = new ServiceHost(typeof(Renderer)))
{
    try
    {
        selfHost.Open();
        ...
        selfHost.Close();

service app.config：

<?xml version="1.0"?>
<configuration>
  <system.serviceModel>
    <services>
      <service name="TestApp.Renderer">
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:9000" />
          </baseAddresses>
        </host>
        <endpoint address="ws" binding="wsHttpBinding" contract="TestApp.IRenderer"/>
        <endpoint kind="udpDiscoveryEndpoint"/>
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior>
          <serviceDiscovery/>
          <serviceMetadata httpGetEnabled="True"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
  </system.serviceModel>
</configuration>

客户端发现代码：

DiscoveryClient discoveryClient = new DiscoveryClient(new UdpDiscoveryEndpoint());
var criteria = new FindCriteria(typeof(IRenderer)) { Duration = TimeSpan.FromSeconds(5) };
var endpoints = discoveryClient.Find(criteria).Endpoints;

“端点”集合始终为空。我尝试过从调试器、从命令行、从管理命令行运行服务和客户端 - 一切，但无济于事（当然，所有这些都在本地计算机上，更不用说我需要它在最终我的整个子网）

任何帮助将不胜感激:-)

Answer 1

这是一个超级简单的发现示例。它不使用配置文件，都是 C# 代码，但您可以将这些概念移植到配置文件中。

在主机和客户端程序之间共享此接口（现在复制到每个程序）

[ServiceContract]
public interface IWcfPingTest
{
  [OperationContract]
  string Ping();
}

将此代码放在主机程序中

public class WcfPingTest : IWcfPingTest
{
  public const string magicString = "djeut73bch58sb4"; // this is random, just to see if you get the right result
  public string Ping() {return magicString;}
}
public void WcfTestHost_Open()
{
  string hostname = System.Environment.MachineName;
  var baseAddress = new UriBuilder("http", hostname, 7400, "WcfPing");
  var h = new ServiceHost(typeof(WcfPingTest), baseAddress.Uri);

  // enable processing of discovery messages.  use UdpDiscoveryEndpoint to enable listening. use EndpointDiscoveryBehavior for fine control.
  h.Description.Behaviors.Add(new ServiceDiscoveryBehavior());
  h.AddServiceEndpoint(new UdpDiscoveryEndpoint());

  // enable wsdl, so you can use the service from WcfStorm, or other tools.
  var smb = new ServiceMetadataBehavior();
  smb.HttpGetEnabled = true;
  smb.MetadataExporter.PolicyVersion = PolicyVersion.Policy15;
  h.Description.Behaviors.Add(smb);

  // create endpoint
  var binding = new BasicHttpBinding(BasicHttpSecurityMode.None);
  h.AddServiceEndpoint(typeof(IWcfPingTest) , binding,   "");
  h.Open();
  Console.WriteLine("host open");
}

将此代码放在

private IWcfPingTest channel;
public Uri WcfTestClient_DiscoverChannel()
{
  var dc = new DiscoveryClient(new UdpDiscoveryEndpoint());
  FindCriteria fc = new FindCriteria(typeof(IWcfPingTest));
  fc.Duration = TimeSpan.FromSeconds(5);
  FindResponse fr = dc.Find(fc);
  foreach(EndpointDiscoveryMetadata edm in fr.Endpoints) 
  {
    Console.WriteLine("uri found = " + edm.Address.Uri.ToString());
  }
  // here is the really nasty part
  // i am just returning the first channel, but it may not work.
  // you have to do some logic to decide which uri to use from the discovered uris
  // for example, you may discover "127.0.0.1", but that one is obviously useless.
  // also, catch exceptions when no endpoints are found and try again.
  return fr.Endpoints[0].Address.Uri;  
}
public void WcfTestClient_SetupChannel()
{
  var binding = new BasicHttpBinding(BasicHttpSecurityMode.None);
  var factory = new ChannelFactory<IWcfPingTest>(binding);
  var uri = WcfTestClient_DiscoverChannel();
  Console.WriteLine("creating channel to " + uri.ToString());
  EndpointAddress ea = new EndpointAddress(uri);
  channel = factory.CreateChannel(ea);
  Console.WriteLine("channel created");
  //Console.WriteLine("pinging host");
  //string result = channel.Ping();
  //Console.WriteLine("ping result = " + result);
}
public void WcfTestClient_Ping()
{
  Console.WriteLine("pinging host");
  string result = channel.Ping();
  Console.WriteLine("ping result = " + result);
}

主机上的客户端程序中，只需调用 WcfTestHost_Open() 函数，然后永远休眠什么的。

在客户端上运行这些函数。主机打开需要一段时间，因此这里有几次延迟。

System.Threading.Thread.Sleep(8000);
this.server.WcfTestClient_SetupChannel();
System.Threading.Thread.Sleep(2000);
this.server.WcfTestClient_Ping();

主机输出应该看起来像

host open

客户端输出应该看起来像

uri found = http://wilkesvmdev:7400/WcfPing
creating channel to http://wilkesvmdev:7400/WcfPing
channel created
pinging host
ping result = djeut73bch58sb4

这确实是我可以为发现示例提出的最小值。这些东西很快就会变得非常复杂。

Answer 2

该死！这是防火墙的原因...由于某种原因，所有 UDP 通信都被阻止 - 禁用防火墙解决了问题。现在我只需要找出正确的防火墙配置......