Announcing Online Events in WCF Service

Vijay Prativadi
12y
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Today, we will implement one of the interesting concept in WCF of how endpoints can be announced and provide availability for the clients to listen who are consuming this service.

Question Arises: What is Announcement Service in WCF?

Endpoints can be announcement as a collection which is available for the client who is consuming the service will be able to listen when comes online/offline Events. Let's get this concept implemented such that we will have a better idea on this

So, let's get it started off now.

The Complete Code of IService1.cs looks like this:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;
namespace WcfService2
{
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IService1" in both code and config file together.
    [ServiceContract]
    public interface IService1
    {
        [OperationContract]
        string Hello(string val);
        [OperationContract]
        string Bye(string val);
    }
}

The Complete Code of Service1.svc.cs looks like this:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;

namespace WcfService2
{
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "Service1" in code, svc and config file together.
    public class Service1 : IService1
    {

        public string Hello(string val)
        {
            return val;
        }

        public string Bye(string val)
        {
            return val;
        }
    }
}

The Complete Code of Web.Config looks like this:

<?xml version="1.0"?>
<configuration>

<system.web>
    <compilation debug="true" targetFramework="4.0" />
</system.web>
<system.serviceModel>
    <behaviors>
      <serviceBehaviors>
        <behavior name="Application">
          <serviceDiscovery>
            <announcementEndpoints>
              <endpoint kind="udpAnnouncementEndpoint"></endpoint>
            </announcementEndpoints>
          </serviceDiscovery>
          
          <serviceMetadata httpGetEnabled="true"/>
          
          <serviceDebug includeExceptionDetailInFaults="false"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
    <services>
      <service name="WcfService2.Service1" behaviorConfiguration="Application">
        <endpoint address="/Simple" binding="basicHttpBinding" contract="WcfService2.IService1"></endpoint>
        <endpoint kind="udpDiscoveryEndpoint"></endpoint>
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:52429/Service1.svc"/>
          </baseAddresses>
        </host>
      </service>
    </services>

</system.serviceModel>
<system.webServer>
<modules runAllManagedModulesForAllRequests="true"/>
</system.webServer>

</configuration>

The Complete Code of Program.cs looks like this

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using ConsoleApplication1.ServiceReference1;
using System.ServiceModel.Discovery;
using System.ServiceModel;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            // Create an AnnouncementService instance
            AnnouncementService announcementService = new AnnouncementService();

            // Subscribe the announcement events
            announcementService.OnlineAnnouncementReceived += OnOnlineEvent;
            announcementService.OfflineAnnouncementReceived += OnOfflineEvent;

            // Create ServiceHost for the AnnouncementService
            using (ServiceHost announcementServiceHost = new ServiceHost(announcementService))
            {
                // Listen for the announcements sent over UDP multicast
                announcementServiceHost.AddServiceEndpoint(new UdpAnnouncementEndpoint());
                announcementServiceHost.Open();
                Service1Client obj = new Service1Client();

Console.WriteLine("The Online is " + obj.Hello("Vijay prativadi"));
Console.WriteLine("The Offline is " + obj.Bye("Vijay prativadi"));

Console.WriteLine("Press <ENTER> to terminate.");

Console.ReadLine();
announcementServiceHost.Close();

}

        }
        static void OnOnlineEvent(object sender, AnnouncementEventArgs e)
        {

            Console.WriteLine("Received an online announcement from {0}",
        e.EndpointDiscoveryMetadata.Address);
            Console.WriteLine("Received an online announcement from {0}", e.EndpointDiscoveryMetadata.ContractTypeNames.ToString());
            Console.WriteLine("Received an online announcement from {0}", e.EndpointDiscoveryMetadata.ListenUris.ToString());
            Console.WriteLine("Received an online announcement from {0}", e.EndpointDiscoveryMetadata.Version);

}

        static void OnOfflineEvent(object sender, AnnouncementEventArgs e)
        {
            Console.WriteLine("Received an offline announcement from {0}",
        e.EndpointDiscoveryMetadata.Address);
            Console.WriteLine("Received an offline announcement from {0}",
        e.EndpointDiscoveryMetadata.ContractTypeNames.ToString());
            Console.WriteLine("Received an offline announcement from {0}", e.EndpointDiscoveryMetadata.ListenUris.ToString());
            Console.WriteLine("Received an offline announcement from {0}", e.EndpointDiscoveryMetadata.Version);