I am trying to create self-hosted System.ServiceModel.Web.WebServiceHost
(.NET 4), however I am running into an issue with the constructor. There are three options:
WebServiceHost()
a parameterless constructor that seems pointless, as there's no way to specify the type of the service, or even the contract. Reflecting on it, it doesn't do anything- just an empty default constructor that doesn't call base.
WebServiceHost(object singletonInstance, params Uri[] baseAddresses)
I don't want a singleton instance, as this is a InstanceContextMode.PerCall
class.
WebServiceHost(System.Type serviceType, params Uri[] baseAddresses)
The type I want to instantiate as a service doesn't have a parameterless constructor (which is a requirement of this method). I'm using NInject to push the parameters into the constructor. However, I'm trying to run this as a self-hosted test, so I want to avoid DI.
Are there any options along these lines, or will I have to not self-host?
To support service classes without parameter-less constructors you need to use an IInstanceProvider
implementation which knows how to create the service class. The code below shows one with the WebServiceHost
, and you can find more about instance providers at http://blogs.msdn.com/b/carlosfigueira/archive/2011/05/31/wcf-extensibility-iinstanceprovider.aspx.
public class StackOverflow_9997163
{
[ServiceContract]
public class Service
{
private int increment;
public Service(int increment)
{
this.increment = increment;
}
[WebGet]
public int Add(int x, int y)
{
return x + y + increment;
}
}
class MyInstanceProvider : IInstanceProvider
{
Func<Service> serviceCreator;
public MyInstanceProvider(Func<Service> serviceCreator)
{
this.serviceCreator = serviceCreator;
}
public object GetInstance(InstanceContext instanceContext, Message message)
{
return this.serviceCreator();
}
public object GetInstance(InstanceContext instanceContext)
{
return this.serviceCreator();
}
public void ReleaseInstance(InstanceContext instanceContext, object instance)
{
}
}
class MyServiceBehavior : IServiceBehavior
{
Func<Service> serviceCreator;
public MyServiceBehavior(Func<Service> serviceCreator)
{
this.serviceCreator = serviceCreator;
}
public void AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, Collection<ServiceEndpoint> endpoints, BindingParameterCollection bindingParameters)
{
}
public void ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
{
foreach (ChannelDispatcher cd in serviceHostBase.ChannelDispatchers)
{
foreach (EndpointDispatcher ed in cd.Endpoints)
{
ed.DispatchRuntime.InstanceProvider = new MyInstanceProvider(this.serviceCreator);
}
}
}
public void Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
{
}
}
public static void Test()
{
string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
WebServiceHost host = new WebServiceHost(typeof(Service), new Uri(baseAddress));
int currentIncrement = 1;
host.Description.Behaviors.Add(new MyServiceBehavior(delegate()
{
return new Service(currentIncrement++);
}));
host.Open();
Console.WriteLine("Host opened");
for (int i = 0; i < 10; i++)
{
WebClient c = new WebClient();
Console.WriteLine(c.DownloadString(baseAddress + "/Add?x=6&y=8"));
}
Console.Write("Press ENTER to close the host");
Console.ReadLine();
host.Close();
}
}