I have a wcf callback programm and it can send a message to a client.
If i try to send a second message the whole programm freezes and i get a timeoutexception.
Here is the servercode:
public void SendMessageToClient(string computerName, string message)
{
foreach (var session in connectedClients.Values)
{
if (session.ComputerName == computerName)
{
var asyncResult = session.Callback.BeginOnMessageReceived(message, new AsyncCallback(OnPushMessageComplete), session.Callback);
if (asyncResult.CompletedSynchronously)
CompletePushMessage(asyncResult);
}
}
}
void OnPushMessageComplete(IAsyncResult asyncResult)
{
CompletePushMessage(asyncResult);
}
void CompletePushMessage(IAsyncResult asyncResult)
{
var callbackChannel = (IServiceCallback)asyncResult.AsyncState;
try
{
callbackChannel.EndOnMessageReceived(asyncResult);
}
catch { }
}
And this is the Callbackinterface:
[OperationContract(IsOneWay = true, AsyncPattern = true)]
IAsyncResult BeginOnMessageReceived(string message, AsyncCallback acb, object state);
void EndOnMessageReceived(IAsyncResult iar);
And this is the client code:
[CallbackBehavior(ConcurrencyMode = ConcurrencyMode.Reentrant, UseSynchronizationContext = false)]
public class ServiceHandler : IServiceCallback
{
public delegate void MessageReceivedHandler(string message);
public event MessageReceivedHandler OnMessageReceivedEvent;
public void OnMessageReceived(string message)
{
if (this.OnMessageReceivedEvent != null)
this.OnMessageReceivedEvent(message);
}
}
void callback_OnMessageReceivedEvent(string message)
{
setlb_info(message)
}
public void setlb_info(string wert)
{
if (this.lb_info.InvokeRequired)
{
setlb_infoCallback d = new setlb_infoCallback(setlb_info);
this.Invoke(d, new object[] { wert });
}
else
{
this.lb_info.Text = wert;
}
}
And if i try this:
Service.CurrentInstance.SendMessageToClient(client_name, message);
the client will get the message but if i call the same method a second time i get the timeoutexception (which is set to 1 minute).
I'm using code from this project(german):
http://www.flexbit.at/blog/wcf-duplex-zwischen-windows-sevice-und-gui-frontend/
I hope someone can help me because i can't finish my work if this function won't work.
Best regards
EDIT: I forgot a code on the client side:
var callback = new ServiceHandler();
callback.OnMessageReceivedEvent += new ServiceHandler.MessageReceivedHandler(callback_OnMessageReceivedEvent);
var callbackInstanceContext = new InstanceContext(callback);
client = new ServiceClient(callbackInstanceContext);
client.Subscribe(System.Environment.MachineName);
Try change
[CallbackBehavior(ConcurrencyMode = ConcurrencyMode.Reentrant, UseSynchronizationContext = false)]
to
[CallbackBehavior(ConcurrencyMode = ConcurrencyMode.Multiple, UseSynchronizationContext = false)]
Related
The addMessage method asynchronously sends messages to clients.
The problem is that those who send it receive it themselves
That is, the client hears himself
public void AddMessage(byte[] message)
{
IAsyncMessageCallback other = OperationContext.Current.GetCallbackChannel<IAsyncMessageCallback>();
other.BeginOnMessageAdded(message, DateTime.Now, delegate (IAsyncResult ar)
{
other.EndOnMessageAdded(ar);
}, null);
}
I tried to implement it in the following way:
public void AddMessage(byte[] message)
{
lock (subscribers)
{
var connection = OperationContext.Current.GetCallbackChannel<IAsyncMessageCallback>();
string user;
if (!subscribers.TryGetValue(connection, out user))
return;
foreach (var other in subscribers.Keys)
{
//Console.WriteLine(other + " " + connection);
if (other == connection)
continue;
Console.WriteLine(other + " " + connection);
other.BeginOnMessageAdded(message, DateTime.Now, delegate (IAsyncResult ar)
{
other.EndOnMessageAdded(ar);
}, null);
Console.WriteLine(message.Length);
}
}
}
But this leads to terrible brakes
Thank you in advance
The essence of the problem:
1.When more than two users enter, the chat starts to hang (a very long delay appears), and then the connection is broken: The communication object System.ServiceModel.Channels.ServiceChannel cannot be used for communication, since its operation is interrupted
If you remove the foreach loop, there will be no breaks and the chat will work calmly with ten users, but the message will be sent to everyone (that is, I will hear my voice in the chat)
Everything works, but with two users. If more come in then System.ServiceModel.Channels.ServiceChannel cannot be used for communication, since its operation is interrupted
public void SendMessage(byte[] message)
{
var connection = OperationContext.Current.GetCallbackChannel<IChatClient>();
string user;
if (!_users.TryGetValue(connection, out user))
return;
foreach (var other in _users.Keys)
{
if (other == connection)
continue;
other.RecievMessage(user, message);
Console.WriteLine(message.Length);
}
}
If you remove the foreach loop, ten users can come in, but they will hear themselves because the server sends this message to everyone indiscriminately.
if the person who sent the video is the current subscriber they don't send the video to THAT subscriber.
How to implement it?
public class StackOverflow_5979252
{
[ServiceContract(Name = "IMessageCallback")]
public interface IAsyncMessageCallback
{
[OperationContract(AsyncPattern = true)]
IAsyncResult BeginOnMessageAdded(string msg, DateTime timestamp, AsyncCallback callback, object asyncState);
void EndOnMessageAdded(IAsyncResult result);
}
[ServiceContract(CallbackContract = typeof(IAsyncMessageCallback))]
public interface IMessage
{
[OperationContract]
void AddMessage(string message);
}
[ServiceBehavior(IncludeExceptionDetailInFaults = true, ConcurrencyMode = ConcurrencyMode.Multiple)]
public class Service : IMessage
{
public void AddMessage(string message)
{
IAsyncMessageCallback callback = OperationContext.Current.GetCallbackChannel<IAsyncMessageCallback>();
callback.BeginOnMessageAdded(message, DateTime.Now, delegate(IAsyncResult ar)
{
callback.EndOnMessageAdded(ar);
}, null);
}
}
class MyClientCallback : IAsyncMessageCallback
{
public IAsyncResult BeginOnMessageAdded(string msg, DateTime timestamp, AsyncCallback callback, object asyncState)
{
Action<string, DateTime> act = (txt, time) => { Console.WriteLine("[{0}] {1}", time, txt); };
return act.BeginInvoke(msg, timestamp, callback, asyncState);
}
public void EndOnMessageAdded(IAsyncResult result)
{
Action<string,DateTime> act = (Action<string,DateTime>)((System.Runtime.Remoting.Messaging.AsyncResult)result).AsyncDelegate;
act.EndInvoke(result);
}
}
static Binding GetBinding()
{
return new NetTcpBinding(SecurityMode.None);
}
public static void Test()
{
string baseAddress = "net.tcp://" + Environment.MachineName + ":8000/Service";
ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
host.AddServiceEndpoint(typeof(IMessage), GetBinding(), "");
host.Open();
Console.WriteLine("Host opened");
InstanceContext instanceContext = new InstanceContext(new MyClientCallback());
DuplexChannelFactory<IMessage> factory = new DuplexChannelFactory<IMessage>(instanceContext, GetBinding(), new EndpointAddress(baseAddress));
IMessage proxy = factory.CreateChannel();
proxy.AddMessage("Hello world");
Console.Write("Press ENTER to close the host");
Console.ReadLine();
((IClientChannel)proxy).Close();
factory.Close();
host.Close();
}
}
My code at the moment looks like this:
Server side:
#region IClientCallback interface
interface IClientCallback
{
[OperationContract(IsOneWay = true)]
void ReceiveWcfElement(WcfElement wcfElement);
}
#endregion
#region IService interface
[ServiceContract(SessionMode = SessionMode.Required, CallbackContract = typeof(IClientCallback))]
interface IService
{
[OperationContract(IsOneWay = true, IsInitiating = false, IsTerminating = false)]
void ReadyToReceive(string userName, int source, string ostatniTypWiadomosci);
[OperationContract(IsOneWay = false, IsInitiating = false, IsTerminating = false)]
bool SendWcfElement(WcfElement wcfElement);
[OperationContract(IsOneWay = false, IsInitiating = true, IsTerminating = false)]
List<int> Login(Client name, string password, bool isAuto, bool isSuperMode);
}
#endregion
#region Public enums/event args
public delegate void WcfElementsReceivedFromClientEventHandler(object sender, WcfElementsReceivedFromClientEventArgs e);
public class WcfElementsReceivedFromClientEventArgs : EventArgs
{
public string UserName;
}
public class ServiceEventArgs : EventArgs
{
public WcfElement WcfElement;
public Client Person;
}
#endregion
#region Service
[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)]
public class Service : IService
{
#region Instance fields
//thread sync lock object
private static readonly Object SyncObj = new Object();
//callback interface for clients
IClientCallback _callback;
//delegate used for BroadcastEvent
public delegate void ChatEventHandler(object sender, ServiceEventArgs e);
public static event ChatEventHandler ChatEvent;
private ChatEventHandler _myEventHandler;
//holds a list of clients, and a delegate to allow the BroadcastEvent to work
//out which chatter delegate to invoke
static readonly Dictionary<Client, ChatEventHandler> Clients = new Dictionary<Client, ChatEventHandler>();
//current person
private Client _client;
#endregion
#region Helpers
private bool CheckIfPersonExists(string name)
{
return Clients.Keys.Any(p => p.UserName.Equals(name, StringComparison.OrdinalIgnoreCase));
}
private ChatEventHandler getPersonHandler(string name)
{
foreach (var c in Clients.Keys.Where(c => c.UserName.Equals(name, StringComparison.OrdinalIgnoreCase)))
{
ChatEventHandler chatTo;
Clients.TryGetValue(c, out chatTo);
return chatTo;
}
return null;
}
private Client GetPerson(string name)
{
return Clients.Keys.FirstOrDefault(c => c.UserName.Equals(name, StringComparison.OrdinalIgnoreCase));
}
#endregion
#region IService implementation
public List<int> Login(Client client, string password, bool isAuto, bool isSuperMode)
{
if (client.ElementsVersions == null)
{
client.ElementsVersions = new WcfElement(WcfElement.RodzajWiadomosci.VersionControl, client.UserName);
}
//create a new ChatEventHandler delegate, pointing to the MyEventHandler() method
_myEventHandler = MyEventHandler;
lock (SyncObj)
{
if (!CheckIfPersonExists(client.UserName))
{
_client = client;
Clients.Add(client, _myEventHandler);
}
else
{
_client = client;
foreach (var c in Clients.Keys.Where(c => c.UserName.Equals(client.UserName)))
{
ChatEvent -= Clients[c];
Clients.Remove(c);
break;
}
Clients[client] = _myEventHandler;
}
_client.LockObj = new object();
}
_callback = OperationContext.Current.GetCallbackChannel<IClientCallback>();
ChatEvent += _myEventHandler;
var rValue = isAuto ? bazaDanych.Login(client.UserName, isSuperMode) : bazaDanych.Login(client.UserName, password);
return rValue;
}
public void PerformDataSync(Client c)
{
WcfElement wcfDelete = null;
WcfElement wcfUpdate = null;
//...
//this method prepares elements for client
//when done it adds them to clients queue (List<WcfElement)
try
{
var counter = 0;
if (wcfDelete != null)
{
foreach (var wcf in WcfElement.SplitWcfElement(wcfDelete, false))//split message into small ones
{
c.AddElementToQueue(wcf, counter++);
}
}
if (wcfUpdate != null)
{
foreach (var wcf in WcfElement.SplitWcfElement(wcfUpdate, true))
{
c.AddElementToQueue(wcf, counter++);
}
}
SendMessageToGui(string.Format("Wstępna synchronizacja użytkownika {0} zakończona.", c.UserName));
c.IsSynchronized = true;
}
catch (Exception e)
{
}
}
private void SendMessageToClient(object sender, EventArgs e)
{
var c = (Client) sender;
if (c.IsReceiving || c.IsSending)
{
return;
}
c.IsReceiving = true;
var wcfElement = c.GetFirstElementFromQueue();
if (wcfElement == null)
{
c.IsReceiving = false;
return;
}
Clients[c].Invoke(this, new ServiceEventArgs { Person = c, WcfElement = wcfElement });
}
public void ReadyToReceive(string userName)
{
var c = GetPerson(userName);
c.IsSending = false;
c.IsReceiving = false;
if (c.IsSynchronized)
{
SendMessageToClient(c, null);
}
else
{
PerformDataSync(c);
}
}
public bool SendWcfElement(WcfElement wcfElement)
{
var cl = GetPerson(wcfElement.UserName);
cl.IsSending = true;
if (wcfElement.WcfElementVersion != bazaDanych.WcfElementVersion) return false;
//method processes messages and if needed creates creates WcfElements which are added to every clients queue
return ifSuccess;
}
#endregion
#region private methods
private void MyEventHandler(object sender, ServiceEventArgs e)
{
try
{
_callback.ReceiveWcfElement(e.WcfElement);
}
catch (Exception ex)
{
}
}
#endregion
}
#endregion
Client side in a moment
#region Client class
[DataContract]
public class Client
{
#region Instance Fields
/// <summary>
/// The UserName
/// </summary>
[DataMember]
public string UserName { get; set; }
[DataMember]
public WcfElement ElementsVersions { get; set; }
private bool _isSynchronized;
public bool IsSynchronized
{
get { return _isSynchronized; }
set
{
_isSynchronized = value;
}
}
public bool IsSending { get; set; }
public bool IsReceiving { get; set; }
private List<WcfElement> ElementsQueue { get; set; }
public object LockObj { get; set; }
public void AddElementToQueue(WcfElement wcfElement, int position = -1)
{
try
{
lock (LockObj)
{
if (ElementsQueue == null) ElementsQueue = new List<WcfElement>();
if (position != -1 && position <= ElementsQueue.Count)
{
try
{
ElementsQueue.Insert(position, wcfElement);
}
catch (Exception e)
{
}
}
else
{
try
{
//dodaje na koncu
ElementsQueue.Add(wcfElement);
}
catch (Exception e)
{
}
}
}
}
catch (Exception e)
{
}
}
public WcfElement GetFirstElementFromQueue()
{
if (ElementsQueue == null) return null;
if (ElementsQueue.Count > 0)
{
var tmp = ElementsQueue[0];
ElementsQueue.RemoveAt(0);
return tmp;
}
return null;
}
#endregion
#region Ctors
/// <summary>
/// Assign constructor
/// </summary>
/// <param name="userName">The userName to use for this client</param>
public Client(string userName)
{
UserName = userName;
}
#endregion
}
#endregion
ProxySingletion:
[CallbackBehavior(ConcurrencyMode = ConcurrencyMode.Reentrant, UseSynchronizationContext = false)]
public sealed class ProxySingleton : IClientCallback
{
#region Instance Fields
private static ProxySingleton _singleton;
public static bool IsConnected;
private static readonly object SingletonLock = new object();
private ServiceProxy _proxy;
private Client _myPerson;
private delegate void HandleDelegate(Client[] list);
private delegate void HandleErrorDelegate();
//main proxy event
public delegate void ProxyEventHandler(object sender, ProxyEventArgs e);
public static event ProxyEventHandler ProxyEvent;
//callback proxy event
public delegate void ProxyCallBackEventHandler(object sender, ProxyCallBackEventArgs e);
public static event ProxyCallBackEventHandler ProxyCallBackEvent;
#endregion
#region Ctor
/// <summary>
/// Blank constructor
/// </summary>
private ProxySingleton()
{
}
#endregion
#region Public Methods
#region IClientCallback implementation
public void ReceiveWcfElement(WcfElement wcfElement)
{
//process received data
//...
ReadyToReceive();
}
#endregion
public void ReadyToReceive()
{
try
{
if (bazaDanych.Dane.Client.IsSending) return;
var w = bazaDanych.Dane.Client.GetFirstElementFromQueue();
if (w != null)
{
SendWcfElement(w);
return;
}
_proxy.ReadyToReceive(bazaDanych.Dane.Client.UserName, source, ostatniTypWiadomosci);
}
catch (Exception)
{
IsConnected = false;
}
}
public static WcfElement CurrentWcfElement;
public bool SendWcfElement(WcfElement wcfElement)
{
if (bazaDanych.Dane.Client.IsReceiving)
{
bazaDanych.Dane.Client.AddElementToQueue(wcfElement);
return true;
}
bazaDanych.Dane.Client.IsSending = true;
foreach (var wcfElementSplited in WcfElement.SplitWcfElement(wcfElement, true))
{
CurrentWcfElement = wcfElementSplited;
try
{
var r = _proxy.SendWcfElement(wcfElementSplited);
CurrentWcfElement = null;
}
catch (Exception e)
{
IsConnected = false;
return false;
}
}
bazaDanych.Dane.Client.IsSending = false;
ReadyToReceive();
return true;
}
public void ListenForConnectOrReconnect(EventArgs e)
{
SendWcfElement(WcfElement.GetVersionElement());//send wcfelement for perform PerformDataSync
ReadyToReceive();
}
public static bool IsReconnecting;
public bool ConnectOrReconnect(bool shouldRaiseEvent = true)
{
if (IsReconnecting)
{
return IsConnected;
}
if (IsConnected) return true;
IsReconnecting = true;
bazaDanych.Dane.Client.IsReceiving = false;
bazaDanych.Dane.Client.IsSending = false;
bazaDanych.Dane.Client.IsSynchronized = false;
try
{
var site = new InstanceContext(this);
_proxy = new ServiceProxy(site);
var list = _proxy.Login(bazaDanych.Dane.Client, bazaDanych.Dane.UserPassword, bazaDanych.Dane.UserIsAuto, bazaDanych.Dane.UserIsSuperMode);
bazaDanych.Dane.UserRights.Clear();
bazaDanych.Dane.UserRights.AddRange(list);
IsConnected = true;
if (shouldRaiseEvent) ConnectOrReconnectEvent(null);
}
catch (Exception e)
{
IsConnected = false;
}
IsReconnecting = false;
return IsConnected;
}
}
#endregion
At the moment my app works like this:
After successful login every client sends WcfElements(which contains bunch of list with ids and versions of elements). Then it sends ReadyToReceive one way message which after login fires performsync method. That method prepares data for client and sends first of them using one way receive method. IF there is more than one wcfelement to send then only last one is marked as last. Client responds with ReadyToReceive after every successful receive from Server. All up to this point works quite well. Problem starts later. Mostly packages are lost (method receiveWcfElement). Server has marked that client is receiving and maybe processing message and is waitng for readytoreceive packet, which will never be send because of lost element.
I've made it like this because as far as I know client can't send and receive at the same time. I've tried this and got this problem:
If client send wcfElement with SendWcfElement method and server due to processing this element created another element which was supposed to be ssend back to client then client whoud have faulted proxy if callback was send before sendWcfElement returned true indicating that method was completed.
Now I wonder if it is possible for client to send and receive at the same time using two way methods ?
I ended up with to services(two connections). One for connection from client to server and another with callback which handles connection from server to client.
I have a WCF Service, And I inspect that using MessageInspector ( inherit IDispatchMessageInspector)
I want to do some thing before running service and result of that ı want not run service.
I want to prevent client call but client dont receive exception.
Can you help me
This scenario looks like the post in the MSDN WCF forum entitled "IDispatchMessageInspector.AfterReceiveRequest - skip operation and manually generate custom response instead". If this is what you need (when you receive a message in the inspector, you decide that you want to skip the service operation, but return a message to the client and the client should not see an exception), then this answer should work for you as well. Notice that you'll need to create the response message in the same format as the client expects, otherwise you'll have an exception.
This code uses three of the (many) WCF extensibility points to achieve that scenario, a message inspector (as you've mentioned you're using), a message formatter and an operation invoker. I've blogged about them in an ongoing series about WCF extensibility at http://blogs.msdn.com/b/carlosfigueira/archive/2011/03/14/wcf-extensibility.aspx.
public class Post_55ef7692_25dc_4ece_9dde_9981c417c94a
{
[ServiceContract(Name = "ITest", Namespace = "http://tempuri.org/")]
public interface ITest
{
[OperationContract]
string Echo(string text);
}
public class Service : ITest
{
public string Echo(string text)
{
return text;
}
}
static Binding GetBinding()
{
BasicHttpBinding result = new BasicHttpBinding();
return result;
}
public class MyOperationBypasser : IEndpointBehavior, IOperationBehavior
{
internal const string SkipServerMessageProperty = "SkipServer";
public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
{
}
public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
{
}
public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
{
endpointDispatcher.DispatchRuntime.MessageInspectors.Add(new MyInspector(endpoint));
}
public void Validate(ServiceEndpoint endpoint)
{
}
public void AddBindingParameters(OperationDescription operationDescription, BindingParameterCollection bindingParameters)
{
}
public void ApplyClientBehavior(OperationDescription operationDescription, ClientOperation clientOperation)
{
}
public void ApplyDispatchBehavior(OperationDescription operationDescription, DispatchOperation dispatchOperation)
{
dispatchOperation.Formatter = new MyFormatter(dispatchOperation.Formatter);
dispatchOperation.Invoker = new MyInvoker(dispatchOperation.Invoker);
}
public void Validate(OperationDescription operationDescription)
{
}
class MyInspector : IDispatchMessageInspector
{
ServiceEndpoint endpoint;
public MyInspector(ServiceEndpoint endpoint)
{
this.endpoint = endpoint;
}
public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
{
Message result = null;
HttpRequestMessageProperty reqProp = null;
if (request.Properties.ContainsKey(HttpRequestMessageProperty.Name))
{
reqProp = request.Properties[HttpRequestMessageProperty.Name] as HttpRequestMessageProperty;
}
if (reqProp != null)
{
string bypassServer = reqProp.Headers["X-BypassServer"];
if (!string.IsNullOrEmpty(bypassServer))
{
result = Message.CreateMessage(request.Version, this.FindReplyAction(request.Headers.Action), new OverrideBodyWriter(bypassServer));
}
}
return result;
}
public void BeforeSendReply(ref Message reply, object correlationState)
{
Message newResult = correlationState as Message;
if (newResult != null)
{
reply = newResult;
}
}
private string FindReplyAction(string requestAction)
{
foreach (var operation in this.endpoint.Contract.Operations)
{
if (operation.Messages[0].Action == requestAction)
{
return operation.Messages[1].Action;
}
}
return null;
}
class OverrideBodyWriter : BodyWriter
{
string bypassServerHeader;
public OverrideBodyWriter(string bypassServerHeader)
: base(true)
{
this.bypassServerHeader = bypassServerHeader;
}
protected override void OnWriteBodyContents(XmlDictionaryWriter writer)
{
writer.WriteStartElement("EchoResponse", "http://tempuri.org/");
writer.WriteStartElement("EchoResult");
writer.WriteString(this.bypassServerHeader);
writer.WriteEndElement();
writer.WriteEndElement();
}
}
}
class MyFormatter : IDispatchMessageFormatter
{
IDispatchMessageFormatter originalFormatter;
public MyFormatter(IDispatchMessageFormatter originalFormatter)
{
this.originalFormatter = originalFormatter;
}
public void DeserializeRequest(Message message, object[] parameters)
{
if (message.Properties.ContainsKey(MyOperationBypasser.SkipServerMessageProperty))
{
Message returnMessage = message.Properties[MyOperationBypasser.SkipServerMessageProperty] as Message;
OperationContext.Current.IncomingMessageProperties.Add(MyOperationBypasser.SkipServerMessageProperty, returnMessage);
OperationContext.Current.OutgoingMessageProperties.Add(MyOperationBypasser.SkipServerMessageProperty, returnMessage);
}
else
{
this.originalFormatter.DeserializeRequest(message, parameters);
}
}
public Message SerializeReply(MessageVersion messageVersion, object[] parameters, object result)
{
if (OperationContext.Current.OutgoingMessageProperties.ContainsKey(MyOperationBypasser.SkipServerMessageProperty))
{
return null;
}
else
{
return this.originalFormatter.SerializeReply(messageVersion, parameters, result);
}
}
}
class MyInvoker : IOperationInvoker
{
IOperationInvoker originalInvoker;
public MyInvoker(IOperationInvoker originalInvoker)
{
if (!originalInvoker.IsSynchronous)
{
throw new NotSupportedException("This implementation only supports synchronous invokers");
}
this.originalInvoker = originalInvoker;
}
public object[] AllocateInputs()
{
return this.originalInvoker.AllocateInputs();
}
public object Invoke(object instance, object[] inputs, out object[] outputs)
{
if (OperationContext.Current.IncomingMessageProperties.ContainsKey(MyOperationBypasser.SkipServerMessageProperty))
{
outputs = null;
return null; // message is stored in the context
}
else
{
return this.originalInvoker.Invoke(instance, inputs, out outputs);
}
}
public IAsyncResult InvokeBegin(object instance, object[] inputs, AsyncCallback callback, object state)
{
throw new NotSupportedException();
}
public object InvokeEnd(object instance, out object[] outputs, IAsyncResult result)
{
throw new NotSupportedException();
}
public bool IsSynchronous
{
get { return true; }
}
}
}
public static void Test()
{
string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
ServiceEndpoint endpoint = host.AddServiceEndpoint(typeof(ITest), GetBinding(), "");
endpoint.Behaviors.Add(new MyOperationBypasser());
foreach (var operation in endpoint.Contract.Operations)
{
operation.Behaviors.Add(new MyOperationBypasser());
}
host.Open();
Console.WriteLine("Host opened");
ChannelFactory<ITest> factory = new ChannelFactory<ITest>(GetBinding(), new EndpointAddress(baseAddress));
ITest proxy = factory.CreateChannel();
Console.WriteLine(proxy.Echo("Hello"));
Console.WriteLine("And now with the bypass header");
using (new OperationContextScope((IContextChannel)proxy))
{
HttpRequestMessageProperty httpRequestProp = new HttpRequestMessageProperty();
httpRequestProp.Headers.Add("X-BypassServer", "This message will not reach the service operation");
OperationContext.Current.OutgoingMessageProperties.Add(
HttpRequestMessageProperty.Name,
httpRequestProp);
Console.WriteLine(proxy.Echo("Hello"));
}
((IClientChannel)proxy).Close();
factory.Close();
Console.Write("Press ENTER to close the host");
Console.ReadLine();
host.Close();
}
}
I have a small WCF pub/sup service running, and remote clients subscribe and send messages (tried will all sorts of complex objects) and that works fine. All interfaces reflect(ed) the type of object being used. Switching to another object type requires that the interfaces be adjusted to accommodate that object type. All subscribers get a copy of the message.
Now I am trying to do the same thing, but with Message class messages. Client creates a new message and encapsulates its object in the message, and sends it to the (remote) service, where it is received properly (inspected the object). However, when the server replies by resending (callback) the message back to the originating client, the client receives the following message:
“The server did not provide a meaningful reply; this might be caused by a contract mismatch, a premature session shutdown or an internal server error.”
Sequence of events (Client):
Client creates Message,
(DuplexChannelFactory)AddMessage,
-Catch above error
Sequence of events (Server):
Service host receives message,
Message inspected (copy and recreate),
Perform callback,
No errors.
Switching back to a basic, or user defined, type and all problems go away. I have been struggling with this for a week now and not closer to any solution. Tried manipulating headers, recreating the message, switching to Message Contracts, and trying to interpret the contents of the trace logs etc. Hope I will find some answers here.
Primary code used (stripped of most of the error handling):
Client interfaces:
namespace WCFSQL
{
public class ClientInterfaces
{
[ServiceContract(Namespace = "WCFServer", Name = "CallBacks")]
public interface IMessageCallback
{
[OperationContract(Name = "OnMessageAdded", Action = "WCFServer/IMessageCallback/OnMessageAdded", IsOneWay = true)]
void OnMessageAdded(Message SQLMessage, DateTime timestamp);
}
[ServiceContract(Namespace = "WCFServer", CallbackContract = typeof(IMessageCallback))]
public interface IMessage
{
[OperationContract(Name = "AddMessage", Action = "WCFServer/IMessage/AddMessage")]
void AddMessage(Message SQLMessage);
[OperationContract(Name = "Subscribe", Action = "WCFServer/IMessage/Subscribe")]
bool Subscribe();
[OperationContract(Name = "Unsubscribe", Action = "WCFServer/IMessage/Unsubscribe")]
bool Unsubscribe();
}
}
}
Server interfaces:
namespace WCFSQL
{
public class ServerInterfaces
{
[ServiceContract(Namespace = "WCFServer")]
public interface IMessageCallback
{
[OperationContract(Name = "OnMessageAdded", Action = "WCFServer/IMessageCallback/OnMessageAdded", IsOneWay = true)]
void OnMessageAdded(Message SQLMessage, DateTime timestamp);
}
[ServiceContract(Namespace = "WCFServer", CallbackContract = typeof(IMessageCallback), SessionMode = SessionMode.Required)]
public interface IMessage
{
[OperationContract(Name = "AddMessage", Action = "WCFServer/IMessage/AddMessage")]
void AddMessage(Message SQLMessage);
[OperationContract(Name = "Subscribe", Action = "WCFServer/IMessage/Subscribe")]
bool Subscribe();
[OperationContract(Name = "Unsubscribe", Action = "WCFServer/IMessage/Unsubscribe")]
bool Unsubscribe();
}
}
}
Message creation:
// client proxy instance created and opened before
public static bool WCFSqlLogger(string Program, WCFSQLErrorLogMessage SQLErrorMessage, WCFSqlClientProxy client)
{
MessageVersion ver = MessageVersion.CreateVersion(EnvelopeVersion.Soap12, AddressingVersion.WSAddressing10);
Message Out = Message.CreateMessage(ver, "WCFServer/IMessage/AddMessage", SQLErrorMessage);
if (!client.SendMessage(Out))
{
Console.WriteLine("Client Main: Unable to send");
return false;
}
return true;
}
Client proxy:
[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, IncludeExceptionDetailInFaults = true)]
[CallbackBehavior(IncludeExceptionDetailInFaults = true, ConcurrencyMode = ConcurrencyMode.Single, UseSynchronizationContext = false)]
public class WCFSqlClientProxy : ClientInterfaces.IMessageCallback, IDisposable
{
public ClientInterfaces.IMessage pipeProxy = null;
DuplexChannelFactory<ClientInterfaces.IMessage> pipeFactory;
public bool Connect()
{
NetTcpBinding newBinding = new NetTcpBinding(SecurityMode.TransportWithMessageCredential);// NetTcpBinding newBinding = new NetTcpBinding(SecurityMode.Transport)
newBinding.Security.Message.ClientCredentialType = MessageCredentialType.Certificate;
EndpointAddress newEndpoint = new EndpointAddress(new Uri("net.tcp://host:8000/ISubscribe"), EndpointIdentity.CreateDnsIdentity("Domain"));
pipeFactory = new DuplexChannelFactory<ClientInterfaces.IMessage>(new InstanceContext(this), newBinding, newEndpoint);
pipeFactory.Credentials.Peer.PeerAuthentication.CertificateValidationMode = X509CertificateValidationMode.PeerOrChainTrust;
pipeFactory.Credentials.ServiceCertificate.Authentication.RevocationMode = X509RevocationMode.NoCheck;
pipeFactory.Credentials.ClientCertificate.SetCertificate(StoreLocation.LocalMachine, StoreName.TrustedPeople, X509FindType.FindByThumbprint, "somestring");
try
{
pipeProxy = pipeFactory.CreateChannel();
pipeProxy.Subscribe();
return true;
}
catch (Exception e)
{
Console.WriteLine("Error opening: {0}", e.Message);
return false;
}
}
public void Close()
{
pipeProxy.Unsubscribe();
}
public bool SendMessage(Message SQLMessage)
{
try
{
Console.WriteLine("Proxy Sending:");
pipeProxy.AddMessage(SQLMessage); // This is where the eror occurs !!!!!!!!!!!!!!!!!!
return true;
}
catch (Exception e)
{
Console.WriteLine("Client Proxy: Error sending: {0}", e.Message);
}
return false;
}
public void OnMessageAdded(Message SQLMessage, DateTime timestamp)
{
WCFSQLErrorLogMessage message = SQLMessage.GetBody<WCFSQLErrorLogMessage>();
Console.WriteLine(message.LogProgram + ": " + timestamp.ToString("hh:mm:ss"));
}
public void Dispose()
{
Console.WriteLine("Dispose: Unsubscribe");
pipeProxy.Unsubscribe();
}
}
Service:
namespace WCFSQL
{
[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, IncludeExceptionDetailInFaults = true)]
[CallbackBehavior(IncludeExceptionDetailInFaults = true, ConcurrencyMode = ConcurrencyMode.Single, UseSynchronizationContext = false)] // or ConcurrencyMode.Reentrant
public class WCFSqlServerProxy : ServerInterfaces.IMessage
{
private static List<ServerInterfaces.IMessageCallback> subscribers = new List<ServerInterfaces.IMessageCallback>();
private static Uri target;
private static ServiceHost serviceHost;
public WCFSqlServerProxy(Uri Target) // Singleton
{
target = Target;
}
public bool Connect()
{
serviceHost = new ServiceHost(typeof(WCFSqlServerProxy), target);
NetTcpBinding newBinding = new NetTcpBinding(SecurityMode.TransportWithMessageCredential);
newBinding.Security.Transport.ClientCredentialType = TcpClientCredentialType.Certificate;
newBinding.Security.Message.ClientCredentialType = MessageCredentialType.Certificate;
serviceHost.Credentials.ClientCertificate.Authentication.RevocationMode = X509RevocationMode.NoCheck; // Non-domain members cannot follow the chain?
serviceHost.Credentials.ServiceCertificate.SetCertificate(StoreLocation.LocalMachine, StoreName.TrustedPeople, X509FindType.FindByThumbprint, "somestring");
serviceHost.Credentials.ClientCertificate.Authentication.CertificateValidationMode = X509CertificateValidationMode.PeerOrChainTrust;
serviceHost.AddServiceEndpoint(typeof(ServerInterfaces.IMessage), newBinding, "ISubscribe");
return true;
}
public bool Open()
{
serviceHost.Open();
return true;
}
public bool Close()
{
serviceHost.Close();
return true;
}
public bool Subscribe()
{
try
{
ServerInterfaces.IMessageCallback callback = OperationContext.Current.GetCallbackChannel<ServerInterfaces.IMessageCallback>();
if (!subscribers.Contains(callback))
{
subscribers.Add(callback);
return true;
}
else
{
return false;
}
}
catch (Exception e)
{
return false;
}
}
public bool Unsubscribe()
{
try
{
ServerInterfaces.IMessageCallback callback = OperationContext.Current.GetCallbackChannel<ServerInterfaces.IMessageCallback>();
if (subscribers.Contains(callback))
{
subscribers.Remove(callback);
return true;
}
return false;
}
catch (Exception e)
{
Console.WriteLine("WCFSqlServerProxy: Unsubscribe - Unsubscribe error {0}", e);
return false;
}
}
private string GetData()
{
MessageProperties messageProperties = ((OperationContext)OperationContext.Current).IncomingMessageProperties;
RemoteEndpointMessageProperty endpointProperty = messageProperties[RemoteEndpointMessageProperty.Name] as RemoteEndpointMessageProperty;
string computerName = null;
try
{
string[] computer_name = Dns.GetHostEntry(endpointProperty.Address).HostName.Split(new Char[] { '.' });
computerName = computer_name[0].ToString();
}
catch (Exception e)
{
computerName = "NOTFOUND";
Console.WriteLine("WCFSqlServerProxy: Hostname error: {0}", e);
}
return string.Format("{0} - {1}:{2}", computerName, endpointProperty.Address, endpointProperty.Port);
}
public void AddMessage(Message SQLMessage) //Go through the list of connections and call their callback funciton
{
subscribers.ForEach(delegate(ServerInterfaces.IMessageCallback callback)
{
if (((ICommunicationObject)callback).State == CommunicationState.Opened)
{
MessageVersion ver = MessageVersion.CreateVersion(EnvelopeVersion.Soap12, AddressingVersion.WSAddressing10);
MessageBuffer buffer = SQLMessage.CreateBufferedCopy(4096);
Message msgCopy = buffer.CreateMessage();
//System.Xml.XmlDictionaryReader xrdr = msgCopy.GetReaderAtBodyContents();
WCFSQLErrorLogMessage p = msgCopy.GetBody<WCFSQLErrorLogMessage>();
SQLMessage = buffer.CreateMessage();
buffer.Close();
Message In = Message.CreateMessage(ver, "WCFServer/IMessage/AddMessage", p); // Tried recreating messsage, with same results
//Console.WriteLine("Message: Header To: {0}", In.Headers.To);
//Console.WriteLine("Message: Header From: {0}", In.Headers.From);
//Console.WriteLine("Message: Header Action: {0}", In.Headers.Action);
//Console.WriteLine("Message: Header ReplyTo: {0}", In.Headers.ReplyTo);
//Console.WriteLine("Message: IsFault: {0}", In.IsFault);
//Console.WriteLine("Message: Properties {0}", In.Properties);
//Console.WriteLine("Message: State {0}", In.State);
//Console.WriteLine("Message: Type {0}", In.GetType());
//Console.WriteLine("Proxy Sending: Copy created");
//Console.WriteLine("Remote: {0}, Hash: {1}", GetData(), callback.GetHashCode());
callback.OnMessageAdded(SQLMessage, DateTime.Now); // This should echo the message back with a timeslot.
}
else
{
Console.WriteLine("WCFSqlServerProxy:addmessage connected state: {0}", ((ICommunicationObject)callback).State == CommunicationState.Opened);
subscribers.Remove(callback);
}
});
}
}
I just got an answer to my question from Tanvir Huda, on the microsoft WCF forum.
"Using the Message Class in Operations
You can use the Message class as an input parameter of an operation, the return value of an operation, or both. If Message is used anywhere in an operation, the following restrictions apply:
•The operation cannot have anyoutorrefparameters.
•There cannot be more than oneinputparameter. If the parameter is present, it must be either Message or a message contract type.
•The return type must be either void,Message, or a message contract type."
I cannot beleive I missed that; must have read it at least three times, but never applied those rules to the callback. The callback in my interfaces described, do have a return type of void, but it has a Message and a DateTime parameter.
After removing the DateTime parameter, the callback did (try) to re-serialize the original Message, but failed because of on invalid action (action was still set for the AddMessage, while now it should be OnMessageAdded). After changing the action on the callback to Action="*" it workt perfectly. A (maybe annoying) detail it that i do not really require a Message type on the callback, but I was very frustrated that I did not get it to work
I'm learning how to use the CCR (Concurrency and Coordination Runtime) in conjunction with a Asynchronous WCF Web Service.
This is the Test WCF Service:
public class Service : IService
{
private Accounts.Manager accountManager = new Accounts.Manager();
public IAsyncResult BeginGetAccount(int id, AsyncCallback callback, object state)
{
//How Do I Call the CCR Function without blocking a Thread?
throw new NotImplementedException();
}
public string EndGetAccount(IAsyncResult result)
{
//How Do I Finish the Call and Pass back the Result?
throw new NotImplementedException();
}
}
It will take a ID number and return the Matching Account Name (if Any)
I have written a CCR function that should find the matching account(s)
(obviously needs a lot of work - this is just proof of concept)
Here is where I come unstuck.
How do I pass back the results (Global port?)
AND more importantly: How do I plug the CCR into the WCF Asynchronous Service Call without blocking a Thread?
public IEnumerator<ITask> GetAccount(int id)
{
SqlDataReader reader = null;
SqlConnection connection = new SqlConnection(#"Data Source=.\SQLEXPRESS;Initial Catalog=BizData;Integrated Security=True;Async=True;");
string query = "SELECT * FROM Account WHERE AccountID = #AccountID";
SqlCommand command = new SqlCommand(query, connection);
SqlParameter accountID = new SqlParameter("AccountID", id);
command.Parameters.Add(accountID);
connection.Open();
yield return Arbiter.Choice(SQLAdapter.GetReader(command),
delegate(SqlDataReader r) { reader = r; },
delegate(Exception e) { Console.Write("Failed to get SQL data"); });
if (reader == null) yield break;
while (reader.Read())
{
Account account = new Account { ID = Convert.ToInt32(reader["AccountID"]),
Name = reader["Account"].ToString(),
ParkingNo = Convert.ToInt32(reader["ParkingNo"]),
Password = reader["Password"].ToString() };
//Post account?
}
connection.Close();
}
OK i finally got somewhere with all of this!
First up: You need a custom AsyncResult Class
class AsyncResult : IAsyncResult , IDisposable
{
object _state;
ManualResetEvent _waitHandle = new ManualResetEvent(false);
bool _isCompleted;
#region IAsyncResult Members
public object AsyncState
{
get { return _state; }
}
public System.Threading.WaitHandle AsyncWaitHandle
{
get { return _waitHandle; }
}
public bool CompletedSynchronously
{
get { return false; }
}
public bool IsCompleted
{
get { return _isCompleted; }
}
#endregion
Exception _exception;
internal Exception Exception
{
get { return _exception; }
}
Accounts.Account _result;
internal Accounts.Account Result
{
get { return _result; }
}
internal AsyncResult(PortSet<Accounts.Account, Exception> port, DispatcherQueue queue, AsyncCallback callback, object state)
{
_state = state;
Arbiter.Activate(queue,
Arbiter.Choice(port,
r =>
{
_result = r;
Complete(callback);
},
e =>
{
_exception = e;
Complete(callback);
}
)
);
}
private void Complete(AsyncCallback callback)
{
_isCompleted = true;
_waitHandle.Set();
if (callback != null)
{
ThreadPool.QueueUserWorkItem(s => callback(this));
}
}
private bool disposedValue = false;
public void Dispose()
{
if (!this.disposedValue)
{
_waitHandle.Close();
_waitHandle = null;
_state = null;
}
this.disposedValue = true;
}
}
Ok, then we need to tie this in with the Async WCF Method calls:
public class Service : IService
{
private Dispatcher dispatcher;
private DispatcherQueue dq;
public Service()
{
dispatcher = new Dispatcher();
dq = new DispatcherQueue("CCR DispatcherQueue", dispatcher);
}
public IAsyncResult BeginGetAccount(int id, AsyncCallback callback, object state)
{
PortSet<Accounts.Account, Exception> port = new PortSet<Accounts.Account, Exception>();
Accounts.Manager manager = new Accounts.Manager();
manager.GetAccountData(dq, port, id);
AsyncResult result = new AsyncResult(port, dq, callback, state);
return result;
}
public string EndGetAccount(IAsyncResult result)
{
{
var AccountName = string.Empty;
if ((result != null))
{
using (Common.AsyncResult asyncResult = result as Common.AsyncResult)
{
if (asyncResult == null)
{
throw new NullReferenceException("IAsynchResult Parameter is Null");
}
asyncResult.AsyncWaitHandle.WaitOne();
if (asyncResult.Result != null)
{
AccountName = asyncResult.Result.Name;
}
}
}
return AccountName;
}
}
}
Then you just need the IEnumerator method to post the answer to the port
see this blog for an end-to-end example:
Exception Handling, Queuing, and UI Synchronization for WCF Services using the CCR