В попытке отточить некоторые примеры сервисов, которые будут использоваться в качестве справочных для наших внутренних сценариев, я создал этот пример дуплексного канала WCF, собрав несколько примеров, обнаруженных за годы.
Дуплексная часть нене работает, и я надеюсь, что мы все сможем понять это вместе.Я ненавижу публиковать столько кода, но чувствую, что сократил его настолько быстро, насколько это возможно для WCF, и включил в себя все части, которые я надеюсь проверить сообществом.Здесь могут быть некоторые действительно плохие идеи, я не говорю, что это правильно, это то, что у меня есть до сих пор.
Есть три части.Канал, Сервер и Клиент.Три проекта, а здесь три файла кода.Нет конфигурации XML, все закодировано. Затем следует вывод кода.
Channel.proj / Channel.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;
namespace Channel
{
public interface IDuplexSyncCallback
{
[OperationContract]
string CallbackSync(string message, DateTimeOffset timestamp);
}
[ServiceContract(CallbackContract = typeof(IDuplexSyncCallback))]
public interface IDuplexSyncContract
{
[OperationContract]
void Ping();
[OperationContract]
void Enroll();
[OperationContract]
void Unenroll();
}
}
Server.proj / Server.cs, ссылки на канал, система.Runtime.Serialization, System.ServiceModel
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;
using System.Timers;
using Channel;
using System.Diagnostics;
using System.Net.Security;
namespace Server
{
class Program
{
// All of this just starts up the service with these hardcoded configurations
static void Main(string[] args)
{
ServiceImplementation implementation = new ServiceImplementation();
ServiceHost service = new ServiceHost(implementation);
NetTcpBinding binding = new NetTcpBinding(SecurityMode.Transport);
binding.Security.Message.ClientCredentialType = MessageCredentialType.Windows;
binding.Security.Mode = SecurityMode.Transport;
binding.Security.Transport.ClientCredentialType = TcpClientCredentialType.Windows;
binding.Security.Transport.ProtectionLevel = ProtectionLevel.EncryptAndSign;
binding.ListenBacklog = 1000;
binding.MaxConnections = 30;
binding.MaxReceivedMessageSize = 2147483647;
binding.ReaderQuotas.MaxStringContentLength = 2147483647;
binding.ReaderQuotas.MaxArrayLength = 2147483647;
binding.SendTimeout = TimeSpan.FromSeconds(2);
binding.ReceiveTimeout = TimeSpan.FromSeconds(10 * 60); // 10 minutes is the default if not specified
binding.ReliableSession.Enabled = true;
binding.ReliableSession.Ordered = true;
service.AddServiceEndpoint(typeof(IDuplexSyncContract), binding, new Uri("net.tcp://localhost:3828"));
service.Open();
Console.WriteLine("Server Running ... Press any key to quit");
Console.ReadKey(true);
service.Abort();
service.Close();
implementation = null;
service = null;
}
}
/// <summary>
/// ServiceImplementation of IDuplexSyncContract
/// </summary>
[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single,
MaxItemsInObjectGraph = 2147483647,
IncludeExceptionDetailInFaults = true,
ConcurrencyMode = ConcurrencyMode.Multiple,
UseSynchronizationContext = false)]
class ServiceImplementation : IDuplexSyncContract
{
Timer announcementTimer = new Timer(5000); // Every 5 seconds
int messageNumber = 0; // message number incrementer - not threadsafe, just for debugging.
public ServiceImplementation()
{
announcementTimer.Elapsed += new ElapsedEventHandler(announcementTimer_Elapsed);
announcementTimer.AutoReset = true;
announcementTimer.Enabled = true;
}
void announcementTimer_Elapsed(object sender, ElapsedEventArgs e)
{
AnnounceSync(string.Format("HELLO? (#{0})", messageNumber++));
}
#region IDuplexSyncContract Members
List<IDuplexSyncCallback> syncCallbacks = new List<IDuplexSyncCallback>();
/// <summary>
/// Simple Ping liveness
/// </summary>
[OperationBehavior]
public void Ping() { return; }
/// <summary>
/// Add channel to subscribers
/// </summary>
[OperationBehavior]
void IDuplexSyncContract.Enroll()
{
IDuplexSyncCallback current = System.ServiceModel.OperationContext.Current.GetCallbackChannel<IDuplexSyncCallback>();
lock (syncCallbacks)
{
syncCallbacks.Add(current);
Trace.WriteLine("Enrollment Complete");
}
}
/// <summary>
/// Remove channel from subscribers
/// </summary>
[OperationBehavior]
void IDuplexSyncContract.Unenroll()
{
IDuplexSyncCallback current = System.ServiceModel.OperationContext.Current.GetCallbackChannel<IDuplexSyncCallback>();
lock (syncCallbacks)
{
syncCallbacks.Remove(current);
Trace.WriteLine("Unenrollment Complete");
}
}
/// <summary>
/// Callback to clients over enrolled channels
/// </summary>
/// <param name="message"></param>
void AnnounceSync(string message)
{
var now = DateTimeOffset.Now;
if (message.Length > 2000) message = message.Substring(0, 2000 - "[TRUNCATED]".Length) + "[TRUNCATED]";
Trace.WriteLine(string.Format("{0}: {1}", now.ToString("mm:ss.fff"), message));
lock (syncCallbacks)
{
foreach (var callback in syncCallbacks.ToArray())
{
Console.WriteLine("Sending \"{0}\" synchronously ...", message);
CommunicationState state = ((ICommunicationObject)callback).State;
switch (state)
{
case CommunicationState.Opened:
try
{
Console.WriteLine("Client said '{0}'", callback.CallbackSync(message, now));
}
catch (Exception ex)
{
// Timeout Error happens here
syncCallbacks.Remove(callback);
Console.WriteLine("Removed client");
}
break;
case CommunicationState.Created:
case CommunicationState.Opening:
break;
case CommunicationState.Faulted:
case CommunicationState.Closed:
case CommunicationState.Closing:
default:
syncCallbacks.Remove(callback);
Console.WriteLine("Removed client");
break;
}
}
}
}
#endregion
}
}
Client.proj / Client.cs, ссылки на канал, System.Runtime.Serialization, System.ServiceModel
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;
using System.Timers;
using System.Diagnostics;
using Channel;
using System.Net;
namespace Client
{
class Program
{
static void Main(string[] args)
{
using (var callbackSyncProxy = new CallbackSyncProxy(new Uri("net.tcp://localhost:3828"), CredentialCache.DefaultNetworkCredentials))
{
callbackSyncProxy.Faulted += (s, e) => Console.WriteLine("CallbackSyncProxy Faulted.");
callbackSyncProxy.ConnectionUnavailable += (s, e) => Console.WriteLine("CallbackSyncProxy ConnectionUnavailable.");
callbackSyncProxy.ConnectionRecovered += (s, e) => Console.WriteLine("CallbackSyncProxy ConnectionRecovered.");
callbackSyncProxy.Ping();
callbackSyncProxy.Ping();
callbackSyncProxy.Ping();
Console.WriteLine("Pings completed. Enrolling ...");
callbackSyncProxy.AnnouncementSyncHandler = AnnouncementHandler;
Console.WriteLine("Enrolled and waiting. Press any key to quit ...");
Console.ReadKey(true); // Wait for quit
}
}
/// <summary>
/// Called by the server through DuplexChannel
/// </summary>
/// <param name="message"></param>
/// <param name="timeStamp"></param>
/// <returns></returns>
static string AnnouncementHandler(string message, DateTimeOffset timeStamp)
{
Console.WriteLine("{0}: {1}", timeStamp, message);
return string.Format("Dear Server, thanks for that message at {0}.", timeStamp);
}
}
/// <summary>
/// Encapsulates the client-side WCF setup logic.
///
/// There are 3 events Faulted, ConnectionUnavailable, ConnectionRecovered that might be of interest to the consumer
/// Enroll and Unenroll of the ServiceContract are called when setting an AnnouncementSyncHandler
/// Ping, when set correctly against the server's send/receive timeouts, will keep the connection alive
/// </summary>
public class CallbackSyncProxy : IDisposable
{
Uri listen;
NetworkCredential credentials;
NetTcpBinding binding;
EndpointAddress serverEndpoint;
ChannelFactory<IDuplexSyncContract> channelFactory;
DisposableChannel<IDuplexSyncContract> channel;
readonly DuplexSyncCallback callback = new DuplexSyncCallback();
object sync = new object();
bool enrolled;
Timer pingTimer = new Timer();
bool quit = false; // set during dispose
// Events of interest to consumer
public event EventHandler Faulted;
public event EventHandler ConnectionUnavailable;
public event EventHandler ConnectionRecovered;
// AnnouncementSyncHandler property. When set to non-null delegate, Enrolls client with server.
// passes through to the DuplexSyncCallback callback.AnnouncementSyncHandler
public Func<string, DateTimeOffset, string> AnnouncementSyncHandler
{
get
{
Func<string, DateTimeOffset, string> temp = null;
lock (sync)
{
temp = callback.AnnouncementSyncHandler;
}
return temp;
}
set
{
lock (sync)
{
if (callback.AnnouncementSyncHandler == null && value != null)
{
callback.AnnouncementSyncHandler = value;
Enroll();
}
else if (callback.AnnouncementSyncHandler != null && value == null)
{
Unenroll();
callback.AnnouncementSyncHandler = null;
}
else // null to null or function to function, just update it
{
callback.AnnouncementSyncHandler = value;
}
}
}
}
/// <summary>
/// using (var proxy = new CallbackSyncProxy(listen, CredentialCache.DefaultNetworkCredentials) { ... }
/// </summary>
public CallbackSyncProxy(Uri listen, NetworkCredential credentials)
{
this.listen = listen;
this.credentials = credentials;
binding = new NetTcpBinding(SecurityMode.Transport);
binding.Security.Message.ClientCredentialType = MessageCredentialType.Windows;
binding.Security.Mode = SecurityMode.Transport;
binding.Security.Transport.ClientCredentialType = TcpClientCredentialType.Windows;
binding.MaxReceivedMessageSize = 2147483647;
binding.ReaderQuotas.MaxArrayLength = 2147483647;
binding.ReaderQuotas.MaxBytesPerRead = 2147483647;
binding.ReaderQuotas.MaxDepth = 2147483647;
binding.ReaderQuotas.MaxStringContentLength = 2147483647;
binding.ReliableSession.Enabled = true;
binding.ReliableSession.Ordered = true;
serverEndpoint = new EndpointAddress(listen);
pingTimer.AutoReset = true;
pingTimer.Elapsed += pingTimer_Elapsed;
pingTimer.Interval = 20000;
}
/// <summary>
/// Keep the connection alive by pinging at some set minimum interval
/// </summary>
void pingTimer_Elapsed(object sender, ElapsedEventArgs e)
{
bool locked = false;
try
{
locked = System.Threading.Monitor.TryEnter(sync, 100);
if (!locked)
{
Console.WriteLine("Unable to ping because synchronization lock could not be aquired in a timely fashion");
return;
}
Debug.Assert(channel != null, "CallbackSyncProxy.channel is unexpectedly null");
try
{
channel.Service.Ping();
}
catch
{
Console.WriteLine("Unable to ping");
}
}
finally
{
if (locked) System.Threading.Monitor.Exit(sync);
}
}
/// <summary>
/// Ping is a keep-alive, but can also be called by the consuming code
/// </summary>
public void Ping()
{
lock (sync)
{
if (channel != null)
{
channel.Service.Ping();
}
else
{
using (var c = new DisposableChannel<IDuplexSyncContract>(GetChannelFactory().CreateChannel()))
{
c.Service.Ping();
}
}
}
}
/// <summary>
/// Enrollment - called when AnnouncementSyncHandler is assigned
/// </summary>
void Enroll()
{
lock (sync)
{
if (!enrolled)
{
Debug.Assert(channel == null, "CallbackSyncProxy.channel is unexpectedly not null");
var c = new DisposableChannel<IDuplexSyncContract>(GetChannelFactory().CreateChannel());
((ICommunicationObject)c.Service).Open();
((ICommunicationObject)c.Service).Faulted += new EventHandler(CallbackChannel_Faulted);
c.Service.Enroll();
channel = c;
Debug.Assert(!pingTimer.Enabled, "CallbackSyncProxy.pingTimer unexpectedly Enabled");
pingTimer.Start();
enrolled = true;
}
}
}
/// <summary>
/// Unenrollment - called when AnnouncementSyncHandler is set to null
/// </summary>
void Unenroll()
{
lock (sync)
{
if (callback.AnnouncementSyncHandler != null)
{
Debug.Assert(channel != null, "CallbackSyncProxy.channel is unexpectedly null");
channel.Service.Unenroll();
Debug.Assert(!pingTimer.Enabled, "CallbackSyncProxy.pingTimer unexpectedly Disabled");
pingTimer.Stop();
enrolled = false;
}
}
}
/// <summary>
/// Used during enrollment to establish a channel.
/// </summary>
/// <returns></returns>
ChannelFactory<IDuplexSyncContract> GetChannelFactory()
{
lock (sync)
{
if (channelFactory != null &&
channelFactory.State != CommunicationState.Opened)
{
ResetChannel();
}
if (channelFactory == null)
{
channelFactory = new DuplexChannelFactory<IDuplexSyncContract>(callback, binding, serverEndpoint);
channelFactory.Credentials.Windows.ClientCredential = credentials;
foreach (var op in channelFactory.Endpoint.Contract.Operations)
{
var b = op.Behaviors[typeof(System.ServiceModel.Description.DataContractSerializerOperationBehavior)] as System.ServiceModel.Description.DataContractSerializerOperationBehavior;
if (b != null)
b.MaxItemsInObjectGraph = 2147483647;
}
}
}
return channelFactory;
}
/// <summary>
/// Channel Fault handler, set during Enrollment
/// </summary>
void CallbackChannel_Faulted(object sender, EventArgs e)
{
lock (sync)
{
if (Faulted != null)
{
Faulted(this, new EventArgs());
}
ResetChannel();
pingTimer.Stop();
enrolled = false;
if (callback.AnnouncementSyncHandler != null)
{
while (!quit) // set during Dispose
{
System.Threading.Thread.Sleep(500);
try
{
Enroll();
if (ConnectionRecovered != null)
{
ConnectionRecovered(this, new EventArgs());
break;
}
}
catch
{
if (ConnectionUnavailable != null)
{
ConnectionUnavailable(this, new EventArgs());
}
}
}
}
}
}
/// <summary>
/// Reset the Channel & ChannelFactory if they are faulted and during dispose
/// </summary>
void ResetChannel()
{
lock (sync)
{
if (channel != null)
{
channel.Dispose();
channel = null;
}
if (channelFactory != null)
{
if (channelFactory.State == CommunicationState.Faulted)
channelFactory.Abort();
else
try
{
channelFactory.Close();
}
catch
{
channelFactory.Abort();
}
channelFactory = null;
}
}
}
// Disposing of me implies disposing of disposable members
#region IDisposable Members
bool disposed;
void IDisposable.Dispose()
{
if (!disposed)
{
Dispose(true);
}
GC.SuppressFinalize(this);
}
void Dispose(bool disposing)
{
if (disposing)
{
quit = true;
ResetChannel();
pingTimer.Stop();
enrolled = false;
callback.AnnouncementSyncHandler = null;
}
disposed = true;
}
#endregion
}
/// <summary>
/// IDuplexSyncCallback implementation, instantiated through the CallbackSyncProxy
/// </summary>
[CallbackBehavior(UseSynchronizationContext = false,
ConcurrencyMode = ConcurrencyMode.Multiple,
IncludeExceptionDetailInFaults = true)]
class DuplexSyncCallback : IDuplexSyncCallback
{
// Passthrough handler delegates from the CallbackSyncProxy
#region AnnouncementSyncHandler passthrough property
Func<string, DateTimeOffset, string> announcementSyncHandler;
public Func<string, DateTimeOffset, string> AnnouncementSyncHandler
{
get
{
return announcementSyncHandler;
}
set
{
announcementSyncHandler = value;
}
}
#endregion
/// <summary>
/// IDuplexSyncCallback.CallbackSync
/// </summary>
[OperationBehavior]
public string CallbackSync(string message, DateTimeOffset timestamp)
{
if (announcementSyncHandler != null)
{
return announcementSyncHandler(message, timestamp);
}
else
{
return "Sorry, nobody was home";
}
}
}
// This class wraps an ICommunicationObject so that it can be either Closed or Aborted properly with a using statement
// This was chosen over alternatives of elaborate try-catch-finally blocks in every calling method, or implementing a
// new Channel type that overrides Disposable with similar new behavior
sealed class DisposableChannel<T> : IDisposable
{
T proxy;
bool disposed;
public DisposableChannel(T proxy)
{
if (!(proxy is ICommunicationObject)) throw new ArgumentException("object of type ICommunicationObject expected", "proxy");
this.proxy = proxy;
}
public T Service
{
get
{
if (disposed) throw new ObjectDisposedException("DisposableProxy");
return proxy;
}
}
public void Dispose()
{
if (!disposed)
{
Dispose(true);
}
GC.SuppressFinalize(this);
}
void Dispose(bool disposing)
{
if (disposing)
{
if (proxy != null)
{
ICommunicationObject ico = null;
if (proxy is ICommunicationObject)
ico = (ICommunicationObject)proxy;
// This state may change after the test and there's no known way to synchronize
// so that's why we just give it our best shot
if (ico.State == CommunicationState.Faulted)
ico.Abort(); // Known to be faulted
else
try
{
ico.Close(); // Attempt to close, this is the nice way and we ought to be nice
}
catch
{
ico.Abort(); // Sometimes being nice isn't an option
}
proxy = default(T);
}
}
disposed = true;
}
}
}
Сортированный вывод:
>> Server Running ... Press any key to quit
Pings completed. Enrolling ... <<
Enrolled and waiting. Press any key to quit ... <<
>> Sending "HELLO? (#0)" synchronously ...
CallbackSyncProxy Faulted. <<
CallbackSyncProxy ConnectionRecovered. <<
>> Removed client
>> Sending "HELLO? (#2)" synchronously ...
8/2/2010 2:47:32 PM -07:00: HELLO? (#2) <<
>> Removed client
Как отметил Эндрю, проблема не столь очевидна.Этот «сопоставленный вывод» не является желаемым выводом.Вместо этого я хотел бы, чтобы сервер работал, Ping и регистрация проходили успешно, а затем каждые 5 секунд сервер "отправлял" ПРИВЕТ?(#m) «синхронно» и немедленно Клиент будет преобразовывать и возвращать, и что Сервер будет получать и распечатывать.
Вместо этого эхо-запросы работают, но сбои Обратного вызова с первой попытки доходят до клиентапри повторном подключении, но не возвращается на сервер, и все отключается.
Единственные исключения, которые я вижу, связаны с тем, что канал ранее вышел из строя и, следовательно, был непригодным для использования, но пока ничего по фактической ошибке, которая вызываетканал для достижения этого состояния.
Я использовал подобный код с [OperationalBehavior(IsOneWay= true)] много раз.Странно, что этот, казалось бы, более распространенный случай вызывает у меня такое горе.
Исключением на стороне сервера, которое я не понимаю, является:
System.TimeoutException: "Эта операция запроса отправлена схемам.microsoft.com / 2005/12 / ServiceModel / Addressing / Anonymous не получили ответ в течение установленного времени ожидания (00:00:00). Время, отведенное для этой операции, могло быть частью более длительного времени ожидания.потому что служба все еще обрабатывает операцию или потому что службе не удалось отправить ответное сообщение. Пожалуйста, рассмотрите возможность увеличения времени ожидания операции (путем преобразования канала / прокси в IContextChannel и установки свойства OperationTimeout) и убедитесь, что служба может подключитьсяклиенту. "