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how can i consume a method from a connected service in .NET WCF and expose it 'AS IS' in a new method in my WCF

My interface look like this:
[ServiceContract]
public interface IMyService
{
[OperationContract]
myConnectedService.SomeComplexResponseType someMethod(myConnectedService.SomeComplexRequestType request);
}
My implementation look like this:
public class MyService : IMyService
{
myConnectedService_client client = new myConnectedService_client();
public myConnectedService.SomeComplexResponseType someMethod(myConnectedService.SomeComplexRequestType request)
{
myConnectedService.SomeComplexResponseType response = client.connectedServiceMethod(request);
return response ;
}
}
The error i get when i am trying to run my service:
Failed to add a service. Service metadata may not be accessible. Make sure your service is running and exposing metadata.
and
error CS0644: 'System.ComponentModel.PropertyChangedEventHandler' cannot derive from special class 'System.MulticastDelegate'

wcf callback reference

I have a desktop app with a duplex WCF service, but I have some troubles using the callback.
The service is started as following in main of program.cs:
ServiceHost svcHost = new ServiceHost(typeof(PeriodicService));
svcHost.Open();
Console.WriteLine("Available Endpoints :\n");
svcHost.Description.Endpoints.ToList().ForEach(endpoint => Console.WriteLine(endpoint.Address.ToString() + " -- " + endpoint.Name));
For the service I created a subscribe function where the callbackchannel is saved in a global variable, then the callback uses that global variable to talk back to the client (there will be only one client connecting).
IPeriodicCallback callbackClient;
public IPeriodicCallback Proxy
{
get
{
return this.callbackClient;
}
}
public void joinPeriodicService()
{
Console.WriteLine("Client subscribe");
this.callbackClient = OperationContext.Current.GetCallbackChannel<IPeriodicCallback>();
}
The thing I want to do now is call the callbackclient from an other class.
In the other class I created the service as:
private PeriodicService periodicService = new PeriodicService();
And I try to write data to it using:
if(this.periodicService.Proxy != null)
{
this.periodicService.Proxy.On1MinuteDataAvailable(tmpPeriod);
}
However the proxy stays null, I also tried to move the proxy part to the class but this also results in it staying null.
When the client connects I nicely get the message "Client Subscribe" but it seems there are two instances running of the periodicservice.
But my problem is I don't see an other way to access the periodicservice then creating it in my class, or is it also already created by the svcHost?
Can ayone point me in the right direction?

This repository shows the a duplex WCF imeplementation I made to answer a similar question a while ago, its a full working example with as little extra stuff as possible.
https://github.com/Aelphaeis/MyWcfDuplexPipeExample
Lets say we have a Service Contract like this :
[ServiceContract(CallbackContract = typeof(IMyServiceCallback),SessionMode = SessionMode.Required)]
public interface IMyService
{
[OperationContract(IsOneWay=true)]
void DoWork();
}
Note that I specified a CallbackContract.
If you want to make a duplex, you would want to perhaps make your Service Behavior implementation of the above contract like this :
[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession)]
public class MyService : IMyService
{
public void DoWork()
{
Console.WriteLine("Hello World");
Callback.WorkComplete();
}
IMyServiceCallback Callback
{
get
{
return OperationContext.Current.GetCallbackChannel<IMyServiceCallback>();
}
}
}
The important thing here is the Callback. This is how your service would allow you to access specified to you by the Client.
You also need to define the callback interface, In my case its quite simple :
[ServiceContract]
public interface IMyServiceCallback
{
[OperationContract(IsOneWay = true)]
void WorkComplete();
}
Now I want to create a client to use this Duplex Service. The first thing I need to do is implement the IMyServiceCallback. I need to do this on the client. In this case the implementation is this:
class Callback : IMyServiceCallback
{
public void WorkComplete()
{
Console.WriteLine("Work Complete");
}
}
Now when I want to open my duplex connection with the services I would create a proxy class like this something like this:
public class MyServiceClient: IMyService, IDisposable
{
DuplexChannelFactory<IMyService> myServiceFactory { get; set; }
public MyServiceClient(IMyServiceCallback Callback)
{
InstanceContext site = new InstanceContext(Callback);
NetNamedPipeBinding binding = new NetNamedPipeBinding();
EndpointAddress endpointAddress = new EndpointAddress(Constants.myPipeService + #"/" + Constants.myPipeServiceName);
myServiceFactory = new DuplexChannelFactory<IMyService>(site, binding, endpointAddress);
}
public void DoWork()
{
myServiceFactory.CreateChannel().DoWork();
}
public void Dispose()
{
myServiceFactory.Close();
}
}
Notice that I specified an InstanceContext. That Instance Context will be an instance of the object I created that implements IMyServiceCallback.
That's all you need to do! Simple as that!
Update :
Callback objects are just like any other object. You can store them into a collection and iterate through them and based on some condition.
One way is to create a property in the IMyServiceCallback that can uniquely identify it. When a client connects to the service it can call a method which specifies a callback object which can then be cached or saved for later use. You can then iterate the callbacks and based on some condition you can call a method for a specific client.
This is certainly more complicated; however, it is certainly manageable. I will add an example in a bit.
Update 2
This is a working example of exactly what you want; however, its a lot more complicated. I'll try to explain as simply as I can : https://github.com/Aelphaeis/MyWcfDuplexPipeExample/tree/MultiClient
Here is a list of the changes:
I've modified the client proxy (and service) so that when initialized it calls the init Method
I've also modified the Service implementation so that now it is a single instance dealing with all requests (for convenience).
I added a new OperationContract in the Service interface called Msg
I've added a new Method in the IMyServiceCallback called RecieveMessage.
I've added a way to identify the client.
In the proxy class I have the following :
public MyServiceClient(IMyServiceCallback Callback)
{
InstanceContext site = new InstanceContext(Callback);
NetNamedPipeBinding binding = new NetNamedPipeBinding();
EndpointAddress endpointAddress = new EndpointAddress(Constants.myPipeService + #"/" + Constants.myPipeServiceName);
myServiceFactory = new DuplexChannelFactory<IMyService>(site, binding, endpointAddress);
Init();
}
public void Init()
{
myServiceFactory.CreateChannel().Init();
}
In my service I have the following :
public class MyService : IMyService
{
public List<IMyServiceCallback> Callbacks { get; private set; }
public MyService(){
Callbacks = new List<IMyServiceCallback>();
}
public void Init()
{
Callbacks.Add(Callback);
}
// and so on
My IMyServiceCallback has been redefined to :
[ServiceContract]
public interface IMyServiceCallback
{
[OperationContract]
int GetClientId();
[OperationContract(IsOneWay = true)]
void WorkComplete();
[OperationContract(IsOneWay = true)]
void RecieveMessage(String msg);
}
By specifying a number, you can contact the client that corresponds with that number. If two clients have the same Id, both clients will be contacted.

WCF ServiceHosts, ServiceEndpoints and Bindings

I currently am running some WCF REST services in a Windows Service (not IIS), using the WebServiceHost. I have a separate interface and class defined for each service, but I'm having some issues understanding how WebServiceHost, ServiceEndpoint and ServiceContracts can be used together to create a selfhosted solution.
The way that I currently set things up is that I create a new WebServiceHost for each class which implements a service and use the name of the class as part of the URI but then define the rest of the URI in the interface.
[ServiceContract]
public interface IEventsService
{
[System.ServiceModel.OperationContract]
[System.ServiceModel.Web.WebGet(UriTemplate = "EventType", ResponseFormat=WebMessageFormat.Json)]
List<EventType> GetEventTypes();
[System.ServiceModel.OperationContract]
[System.ServiceModel.Web.WebGet(UriTemplate = "Event")]
System.IO.Stream GetEventsAsStream();
}
public class EventsService: IEventsService
{
public List<EventType> GetEventTypes() { //code in here }
public System.IO.Stream GetEventsAsStream() { // code in here }
}
The code to create the services looks like this:
Type t = typeof(EventService);
Type interface = typeof(IEventService);
Uri newUri = new Uri(baseUri, "Events");
WebServicesHost host = new WebServiceHost(t, newUri);
Binding binding = New WebHttpBinding();
ServiceEndpoint ep = host.AddServiceEndpoint(interface, binding, newUri);
This works well and the service endpoint for each service is created at an appropriate url.
http://XXX.YYY.ZZZ:portnum/Events/EventType
http://XXX.YYY.ZZZ:portnum/Events/Event
I then repeat for another service interface and service class. I would like to remove the Events in the Url though but if I do that and create multiple WebServiceHosts with the same base URL I get the error:
The ChannelDispatcher at 'http://localhost:8085/' with contract(s) '"IOtherService"' is unable to open its IChannelListener
with the internal Exception of:
"A registration already exists for URI 'http://localhost:8085/'."
I'm trying to understand how the WebServiceHost, ServiceEndpoint and ServiceContract work together to create the ChannelListener.
Do I need a separate WebServiceHost for each class which implements a service? I don't see a way to register multiple types with a single WebServiceHost
Secondly, I'm passing in the interface to the AddServceEndpoint method and I assume that method checks the object for all of the OperationContract members and adds them, the problem is how does the WebServiceHost know which class should map to which interface.
What I would love would be an example of creating a WCF self hosted service which runs multiple services while keeping the interface and the implementation classes separate.

Sounds to me like the problem that you are having is you are trying to register more than one service on the same service URI. This will not work, as you have noticed, each service must have a unique endpoint.
Unique By
IP
Domain
Port Number
Full URL
Examples
http://someserver/foo -> IFoo Service
http://someserver/bar -> IBar Service
http://somedomain -> IFoo Service
http://someotherdomain -> IBar Service
http://somedomain:1 -> IFoo Service
http://somedomain:2 -> IBar Service
You get the idea.
So to directly address your question, if you want more than once service to be at the root url for you site, you will have to put them on different ports. So you could modify your code to be something like
public class PortNumberAttribute : Attribute
{
public int PortNumber { get; set; }
public PortNumberAttribute(int port)
{
PortNumber = port;
}
}
[PortNumber(8085)]
public interface IEventsService
{
//service methods etc
}
string baseUri = "http://foo.com:{0}";
Type iface = typeof(IEventsService);
PortNumberAttribute pNumber = (PortNumberAttribute)iface.GetCustomAttribute(typeof(PortNumberAttribute));
Uri newUri = new Uri(string.Format(baseUri, pNumber.PortNumber));
//create host and all that

I think it might be useful for you to re-think about your URI approach. Uri is a unique resource identifier.
Each your endpoint says that you try to expose outside a different kind of resource it's "Events" and "OtherResource". Thus you need to change your UriTemplates a bit.
I would make it so:
[ServiceContract]
public interface IEventTypesService
{
[OperationContract]
[WebGet(UriTemplate = "", ResponseFormat=WebMessageFormat.Json)]
IList<EventType> GetEventTypes();
[OperationContract]
[WebGet(UriTemplate = "{id}")]
EventType GetEventType(string id);
}
[ServiceContract]
public interface IEventsService
{
[OperationContract]
[WebGet(UriTemplate = "")]
Stream GetEventsAsStream();
[OperationContract]
[WebGet(UriTemplate = "{id}")]
Event GetEvent(string id);
}
public class EventsService: IEventsService, IEventTypesService
{
public IList<EventType> GetEventTypes() { //code in here }
public EventType GetEventType(string id) { //code in here }
public Stream GetEventsAsStream() { // code in here }
public EventType GetEventType(string id) { // code in here }
}
Type t = typeof(EventService);
Type interface1 = typeof(IEventsService);
Type interface2 = typeof(IEventTypesService);
var baseUri = new Uri("http://localhost");
Uri eventsUri= new Uri(baseUri, "Events");
Uri eventTypesUri= new Uri(baseUri, "EventTypes");
WebServicesHost host = new WebServiceHost(t, baseUri);
Binding binding = New WebHttpBinding();
host.AddServiceEndpoint(interface1, binding, eventsUri);
host.AddServiceEndpoint(interface2, binding, eventTypesUri);
And yes, you are right - you have to have different addresses, but it's really different resources. To understand it better you can refer: RESTful API Design, best-practices-for-a-pragmatic-restful-api
To finish, there is a way to use the same address, but the approach a bit weird:
Using the same address

The following solution:
allows a single object to handle a specific endpoint
no part of the path is in the URI template
uses the same port for all of the services
It does requires more than one WebServiceHost - one per object that handles requests. Another difficulty is that adding deeper endpoints (like /events/2014) means they either need to have unique parameters or the URI template must include part of the path, if you go convention over configuration that shouldn't be a problem.
A WebServiceHost can only host one thing (class) but that object can have multiple interfaces to handle multiple different types of requests on different URLs. How can different WebServiceHosts bind to the same domain:port? They can't so I guess WebServiceHost wraps an underlying static object that routes requests to the right object. This doesn't technically answer your question but I think this implementation allows you to do what you want right?
A console app that hosts the web services.
public class Program
{
static void Main (string[] args)
{
var venueHost = new WebServiceHost (typeof (Venues));
venueHost.AddServiceEndpoint (typeof (IVenues), new WebHttpBinding (), "http://localhost:12345/venues");
venueHost.Open ();
var eventHost = new WebServiceHost (typeof (Events));
eventHost.AddServiceEndpoint (typeof (IEvents), new WebHttpBinding (), "http://localhost:12345/events");
eventHost.Open ();
while (true)
{
var k = Console.ReadKey ();
if (k.KeyChar == 'q' || k.KeyChar == 'Q')
break;
}
}
}
The Venues class implements IVenues and handles any requests to http://localhost:12345/venues/
[ServiceContract]
public interface IVenues
{
[WebInvoke (Method = "GET", UriTemplate = "?id={id}")]
string GetVenues (string id);
}
public class Venues : IVenues
{
public string GetVenues (string id)
{
return "This would contain venue data.";
}
}
The Events class implements IEvents and handles any requests to http://localhost:12345/events/
[ServiceContract]
public interface IEvents
{
[WebInvoke (Method = "GET", UriTemplate = "?venue={venue}")]
string GetEvents (string venue);
}
public class Events : IEvents
{
public string GetEvents (string venue)
{
return "This would contain event data.";
}
}

WCF self hosting can be done in many ways like Console application hosting, Windows service hosting, etc.
I had tried to host two services using a single console application. The structure of the services was similar to what you mentioned, that is, separate classes and interfaces for both the services.
You might want to have a look at this link:
Hosting two WCf services using one console app

TDD the WCF service class itself first

So I started to create TDD tests for a new WCF service I wanted to create. In TDD, you create the test, and start adding objects that don't exist yet into your tests. First object I wanted to test was that the service is not null after instantiated.
Then then I said wait, how the hell can you do that in WCF...a service extension is .svc. Yes there's a .svc.cs but the main parent is .svc. I don't see a way I can to TDD on this part where you've have something like this but it'd create an .svc instead of just a .cs:
[TestMethod]
public void UponInitialization_ServiceIsNotNull()
{
// Arrange
// Act
NyNewService service = new MyNewService();
// Assert
Assert.IsTrue(service != null);
}
This is a very fundamental necessary first test, testing the very simplest possible from the start...this is very common on any TDD or XP team doing TDD.
Any thoughts on how I can create a new .svc from within my test here? not a plain .cs?

I'd start with creating acceptance test for non-existing WCF service:
private Uri _baseAddress = new Uri("http://localhost:8713/service1");
private IService1 _client;
[SetUp]
public void Setup()
{
var binding = new BasicHttpBinding();
var endpoint = new EndpointAddress(_baseAddress);
var factory = new ChannelFactory<IService1>(binding, endpoint);
_client = factory.CreateChannel();
}
[TearDown]
public void TearDown()
{
if (_client != null)
((ICommunicationObject)_client).Close();
}
[Test]
public void ShouldReturnSampleData()
{
Assert.That(_client.GetData(42), Is.EqualTo("You entered: 42"));
}
Keep in mind, that nothing is created yet - we start from test. Now you can create service interface:
public interface IService1
{
string GetData(int value);
}
Test now compiles, but of course, it fails with error
Attempted to get contract type for IService1, but that type is not a
ServiceContract, nor does it inherit a ServiceContract.
Good, that's because we should mark our interface with [ServiceContract] attribute. We add this attribute and run test again:
Method GetData is not supported on this proxy, this can happen if the
method is not marked with OperationContractAttribute or if the
interface type is not marked with ServiceContractAttribute.
Ok, mark our service interface with required attributes:
[ServiceContract]
public interface IService1
{
[OperationContract]
string GetData(int value);
}
Now we see another error (because nothing is actually running our non-existing service)
There was no endpoint listening at http://localhost:8713/service1 that
could accept the message. This is often caused by an incorrect address
or SOAP action. See InnerException, if present, for more details.
We can use ServiceHost to run our service (at this moment we need to create service class to compile tests):
private ServiceHost _host;
[SetUp]
public void Setup()
{
_host = new ServiceHost(typeof(Service1), _baseAddress);
ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
smb.HttpGetEnabled = true;
smb.MetadataExporter.PolicyVersion = PolicyVersion.Policy15;
_host.Description.Behaviors.Add(smb);
_host.Open();
// creating client as above
}
[TearDown]
public void TearDown()
{
// closing client as above
if (_host != null)
_host.Close();
}
You also need to implement IService1 interface by service class (otherwise test will fail):
public class Service1 : IService1
{
public string GetData(int value)
{
throw new NotImplementedException();
}
}
Now I'd created some unit-tests for Service1 class in order to implement GetData functionality. With these tests passing you will have acceptance test passing also. Thats it. You did test first, and your WCF service is completely ready to be hosted.

NetNamedPipeBinding: parameter in pipe method is empty

I have a ServiceHost listening on a NetNamedPipeBinding endpoint. I have a service contract class with a single method which is being called by the client and handled by the server. The method (We'll call it PipeRequest()) has a Request parameter. On the client side I populate this object but it's empty by the time it gets sent over to the server. Any ideas why this would be the case?
_Host = new ServiceHost(typeof(PipeService), new Uri(ServiceRequestRouter.URI));
_Host.AddServiceEndpoint(
typeof(IPipeService),
new NetNamedPipeBinding(),
_PipeName
);
_Host.Open();
[ServiceContract(Namespace = "http://www.example.com/PipeCommunication")]
interface IPipeService
{
[OperationContract]
void PipeRequest(ServiceRequestBase request);
}
[DataContract]
[KnownType(typeof(DerivedServiceRequest))]
[KnownType(typeof(SomeEnumType))]
public abstract class ServiceRequestBase
{
...
public void Dispatch(string pPipeName = ServiceRequestRouter.DefaultPipeName)
{
EndpointAddress epa = new EndpointAddress(_address_));
IPipeService proxy = ChannelFactory<IPipeService>.CreateChannel(new NetNamedPipeBinding(), epa);
proxy.PipeRequest(this);
}
}

It look like it has to do with proxy.PipeRequest(this);
You need to pass in a class that inherits ServiceRequestBase, if you class does inherit the ServiceRequestBase then it might not be serializable.

It turns out I had to specify (as part of the data contract) any derived classes from ServiceRequestBase class.
[DataContract]
[KnownType(typeof(CitrixInfoServiceRequest))] // added this line
[KnownType(typeof(RegStateServiceRequest))] // added this line
public abstract class ServiceRequestBase
{
// ...
}