WCF心跳判斷服務(wù)端及客戶端是否掉線并實現(xiàn)重連接

若掉線時服務(wù)器或客戶端又在線時將實現(xiàn)自動重連；將通過WCF的雙工知識以及相應(yīng)的心跳包來實現(xiàn)此功能；

首先了解一下本實例的一個分層架構(gòu)圖；相信了解WCF對這個分層法肯定都很了解；其中Client為客戶端，Interface為契約層，Service則是實現(xiàn)契約的服務(wù)層；

接下來我們將對各層進行一個簡單的講解

首先我們了解契約層Interface；因為我們利用WCF中的雙工知識，所以此處我們定義的兩個接口，其中ICallback為回調(diào)接口；IPushMessage上面定義的回調(diào)；我們發(fā)現(xiàn)回調(diào)接口上并沒有定義ServiceContract; 其實是WCF當一個接口被定義成回調(diào)接口時已經(jīng)默認了；

using System.ServiceModel;
namespace Interface
{
    [ServiceContract(SessionMode=SessionMode.Required,CallbackContract=typeof(ICallback))]
    public interface IPushMessage
    {
        [OperationContract(IsOneWay = true)]
        void Login(string UID);

        [OperationContract(IsOneWay = true)]
        void Update(string UID);

        [OperationContract(IsOneWay = true)]
        void Leave(string UID);
    }
}

using System.ServiceModel;
namespace Interface
{
    public interface ICallback
    {
        [OperationContract(IsOneWay = true)]
        void ShowMessage(string msg);
    }
}

接著我們了解一下實現(xiàn)契約的服務(wù)層Service;此處包括實現(xiàn)接口IPushMessage的服務(wù)內(nèi)容，還定義一個類WcfCleint；在PushMessageServer服務(wù)內(nèi)里我們定義的一個靜態(tài)成員Dictionary<string,WcfCleint>用于記錄我們客戶端上下線的操作；定義的一個lockObje用來鎖定每個操作,在最后我們還定義的一個定時器用來判斷客戶端用戶是否脫機了；其中方法Update()我們就實現(xiàn)的雙工中的回調(diào)；

using System.ServiceModel;
using Interface;
namespace Service
{
    public class PushMessageServer:IPushMessage
    {
        static Dictionary<string, WcfCleint> dit_callback = new Dictionary<string, WcfCleint>();

        private static Object lockObje = new Object();

        public void Login(string UID)
        {
            Console.WriteLine("用戶:" + UID + "上線");
            lock (lockObje)
            {
                dit_callback.Add(UID, new WcfCleint(OperationContext.Current.GetCallbackChannel<ICallback>(), DateTime.Now));
            }
        }

        public void Update(string UID)
        {
            ICallback callback = OperationContext.Current.GetCallbackChannel<ICallback>();
            Console.WriteLine("用戶:" + UID + "心跳更新！");
            lock (lockObje)
            {
                if (dit_callback.ContainsKey(UID))
                {
                    dit_callback.Remove(UID);
                }
                dit_callback.Add(UID, new WcfCleint(OperationContext.Current.GetCallbackChannel<ICallback>(), DateTime.Now));
                callback.ShowMessage(UID);
            }
        }

        public void Leave(string UID)
        {
            Console.WriteLine("用戶:" + UID + "退出！");
            lock (lockObje)
            {
                dit_callback.Remove(UID);
            }
        }

        static System.Timers.Timer timer1;
        public static void StartListenClients()
        {
            timer1 = new System.Timers.Timer();
            timer1.Interval = 500;
            timer1.Elapsed += new System.Timers.ElapsedEventHandler(time_EventArgs);
            timer1.Start();
        }

        static void time_EventArgs(object sender, System.Timers.ElapsedEventArgs e)
        {
            lock (lockObje)
            {
                foreach (string key in new List<string>(dit_callback.Keys))
                {
                    if (dit_callback[key].NowdateTime.AddSeconds(5) < DateTime.Now)
                    {
                        dit_callback.Remove(key);
                        Console.WriteLine("脫機用戶" + key);
                    }
                }
            }
        }
    }
}

接著我們簡單看一下WcfCleint的代碼：

using Interface;
using System.ServiceModel;
namespace Service
{
    public class WcfCleint
    {
        public DateTime NowdateTime { get; set; }
        public ICallback callbackHandler { get; set; }

        public WcfCleint(ICallback callback, DateTime nowTime)
        {
            this.callbackHandler = callback;
            this.NowdateTime = nowTime;
        }
    }
}

服務(wù)端的配置文件信息，此處我們采用net.tcp方式：

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.serviceModel>
    <behaviors>
      <serviceBehaviors>
        <behavior name="exposeExceptionDetail">
          <serviceDebug includeExceptionDetailInFaults="true"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <services>
      <service name="Service.PushMessageServer"
               behaviorConfiguration="exposeExceptionDetail">
        <endpoint address="net.tcp://127.0.0.1:3721/PushMessageServer"
                  binding="netTcpBinding"
                  contract="Interface.IPushMessage"/>
      </service>
    </services>
  </system.serviceModel>
</configuration>

服務(wù)端的運行入口代碼，通過一個線程不斷的運行：

using System.Threading;
using System.ServiceModel.Description;
namespace Service
{
    class Program
    {
        static void Main(string[] args)
        {
            using (ServiceHost host = new ServiceHost(typeof(PushMessageServer)))
            {
                host.Open();
                Console.WriteLine("WCF心跳包實現(xiàn)開始監(jiān)聽");
                PushMessageServer.StartListenClients();
                int i = 0;
                while (true)
                {
                    System.Threading.Thread.Sleep(2000);
                    i++;
                }
                Console.Read();
                host.Abort();
                host.Close();
            }
        }
    }
}

接著了解客戶端層的情況；首先是一個實現(xiàn)的回調(diào)接口的內(nèi)容類；

using Interface;
namespace Client
{
    public class CallServer:ICallback
    {
        public void ShowMessage(string msg)
        {
            Console.WriteLine("服務(wù)器正在工作中；" + msg);
        }
    }
}

客戶端的配置信息如下：

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.serviceModel>
    <client>
      <endpoint name="pushmessageserver"
                address="net.tcp://127.0.0.1:3721/PushMessageServer"
                binding="netTcpBinding"
                contract="Interface.IPushMessage"/>
    </client>
  </system.serviceModel>
</configuration>

客戶端的運行入口代碼如下，它會判斷服務(wù)器是否掉線，若掉線會試著重連：

using System.ServiceModel;
using Interface;
using System.ServiceModel.Channels;
using System.Threading;
namespace Client
{
    class Program
    {
        static void Main(string[] args)
        {
            InstanceContext callback = new InstanceContext(new CallServer());
            using (DuplexChannelFactory<IPushMessage> channelFactory = new DuplexChannelFactory<IPushMessage>(callback, "pushmessageserver"))
            {
                IPushMessage proxy = channelFactory.CreateChannel();
                using (proxy as IDisposable)
                {
                    string UID = "踏浪帥";
                    proxy.Login(UID);

                    while (true)
                    {
                        Thread.Sleep(3000);
                        try
                        {
                            proxy.Update(UID);
                        }
                        catch
                        {
                            try
                            {
                                Console.WriteLine("正在重連");
                                proxy = channelFactory.CreateChannel();
                                proxy.Login(UID);
                            }
                            catch
                            {
                                Console.WriteLine("重連異常");
                            }
                        }
                    }
                }
            }
            Console.Read();
        }
    }
}

運行的效果：

1：首先運行服務(wù)端，讓其處于監(jiān)聽

2：接著運行客戶端，客戶端會顯示服務(wù)器正在工作中以及當前的賬號

3：當客戶端上線后，服務(wù)端就發(fā)現(xiàn)客戶端用戶，并顯示出來，不停的進行判斷

4：當我們把服務(wù)端停掉以后，此時服務(wù)是不工作的，我們可以看到客戶端就會不停的嘗試著重連服務(wù)端；

5：當我們重新把服務(wù)端打開以后，服務(wù)端會自運發(fā)現(xiàn)正在運行的客戶端信息；

6：上面我們重新打開服務(wù)端，我們可以在客戶端發(fā)現(xiàn)它重連接服務(wù)端成功并顯示如下：

7：接著我們將把客戶端關(guān)閉；我們會在服務(wù)端發(fā)現(xiàn)它提示客戶端的用戶脫機了；

8：此時服務(wù)端還是不停的監(jiān)聽中，我們再把客戶端打開，服務(wù)端將會接著顯示用戶；