WCF心跳判断服务端及客户端是否掉线并实现重连接

本篇文章将通过一个实例实现对WCF中针对服务端以及客户端是否掉线进行判断；若掉线时服务器或客户端又在线时将实现自动重连；将通过WCF的双工知识以及相应的心跳包来实现此功能；

首先了解一下本实例的一个分层架构图；相信了解WCF对这个分层法肯定都很了解；其中Client为客户端，Interface为契约层，Service则是实现契约的服务层；

接下来我们将对各层进行一个简单的讲解；方便大家理解实例的实现方式；

首先我们了解契约层Interface；因为我们利用WCF中的双工知识，所以此处我们定义的两个接口，其中ICallback为回调接口；IPushMessage上面定义的回调；我们发现回调接口上并没有定义ServiceContract; 其实是WCF当一个接口被定义成回调接口时已经默认了；

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); }}

接着我们了解一下实现契约的服务层Service;此处包括实现接口IPushMessage的服务内容，还定义一个类WcfCleint；在PushMessageServer服务内里我们定义的一个静态成员Dictionary<string,WcfCleint>用于记录我们客户端上下线的操作；定义的一个lockObje用来锁定每个操作,在最后我们还定义的一个定时器用来判断客户端用户是否脱机了；其中方法Update()我们就实现的双工中的回调；

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("用户:" + UID + "上线"); 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("用户:" + 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("用户:" + 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("脱机用户" + key); } } } } }}

接着我们简单看一下WcfCleint的代码：

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; } }}

服务端的配置文件信息，此处我们采用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>

服务端的运行入口代码，通过一个线程不断的运行：

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心跳包实现开始监听"); PushMessageServer.StartListenClients(); int i = 0; while (true) { System.Threading.Thread.Sleep(2000); i++; } Console.Read(); host.Abort(); host.Close(); } } }}

接着了解客户端层的情况；首先是一个实现的回调接口的内容类；

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

客户端的配置信息如下：

<?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>

客户端的运行入口代码如下，它会判断服务器是否掉线，若掉线会试着重连：

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 = "踏浪帅"; proxy.Login(UID); while (true) { Thread.Sleep(3000); try { proxy.Update(UID); } catch { try { Console.WriteLine("正在重连"); proxy = channelFactory.CreateChannel(); proxy.Login(UID); } catch { Console.WriteLine("重连异常"); } } } } } Console.Read(); } }}

代码的内容就如上，接着我们简单看一下运行的效果：

1：首先运行服务端，让其处于监听

WCF心跳判断服务端及客户端是否掉线并实现重连接