我正在尝试创建自托管的System.ServiceModel.Web.WebServiceHost
(.NET 4),但是我遇到了构造函数的问题。有三种选择:
-
WebServiceHost()
是一个似乎毫无意义的无参数构造函数,因为无法指定服务的类型,甚至无法指定契约。反思一下,它什么也不做——只是一个不调用base的空默认构造函数。 -
WebServiceHost(object singletonInstance, params Uri[] baseAddresses)
我不想要一个singleton实例,因为这是一个InstanceContextMode.PerCall
类。 -
WebServiceHost(System.Type serviceType, params Uri[] baseAddresses)
我想实例化为服务的类型没有无参数构造函数(这是该方法的要求)。我正在使用NInject将参数推送到构造函数中。然而,我正试图将其作为一个自托管测试来运行,所以我想避免DI。
沿着这些路线有什么选择吗,或者我将不得不不自我主持?
要支持没有无参数构造函数的服务类,需要使用知道如何创建服务类的IInstanceProvider
实现。下面的代码显示了一个带有WebServiceHost
的实例提供者,您可以在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();
}
}